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COPYRIGHT DEPOSIT. 



Manual of 
General Agriculture 



BY 

EDWARD P. TERRY, M. S. 



Los Angeles City Schools 



LOS ANGELES, CALIFORNIA 



SI, 6 



4 



COPYRIGHT, 1912 BY 
EDWARD P. TERRY 



TIMES-MIRROR PTG. ft BDG. HOUSE. LOS ANGELES. CAU 



t.aA32?4'^3 



INTRODUCTION 

The experiments in this manual represent actual 
work done by the author's classes during several years 
teaching of the subject of general agriculture in High 
Schools in Northern and Southern California. There is 
sufficient material to occupy the laboratory time of a 
High School class at least four periods a week for one 
year. Not all the exercises are suitable for any one 
locality, but nearly all can be used any place. The 
manual is not intended to displace any text. 

A satisfactory plan for conducting a course in gen- 
eral agriculture is to have each student own a manual and 
have the school furnish the references to accompany it. 
As the recitations do not occur every day, one book for 
three students will be found sufficient. Usually the local 
library will supply a portion of the books needed. A list 
of references will be found in the back of this manual. 

A note book containing a record of each exercise per- 
formed should be kept by the student. The following 
form is suggested : 

Number and statement of exercise. 

Exercise. 

Result. 

Conclusion. 
It is unnecessary for the student to copy materials. 
At the beginning of nearly all the exercises will be found 
a list of materials needed, but special attention is called 
to the following, the materials for which cannot be ob- 
tained at once : 46, 56, 57, 58, 59, 62, 63, 64, 67, 68, 69. 

The author wishes to express his thanks for council 
and material contributed by Principal E. L. Mitchel, Pro- 
fessors W. T. Clarke, R. H. Loughridge, A. D. MacGil- 
livray, H. H. Whetzel, C. S. Wilson, E. G. Montgomery, 
Messrs. A. R. Tyler, Geo. C. Roeding and Miss May Kimble. 
The cuts under Budding and Grafting were taken from 
Farmers' Bulletin No. 157. With slight changes, exer- 
cises 31, 32, 33, 34, 45, 46, 47 and 50 are by Prof. F. E. 
Edwards. 



CONTENTS 



PART I. PHYSICAL PROPERTIES OF SOILS. 

Page 

1. How Soils are Formed 7 

2. Taking Soil Samples 7 

3. Microscopical Examination of Soil Particles. ... 8 

4. Determination of Total Moisture in the Soil ... 9 

5. Capillarity 10 

6. Effect of Drainage on Soil Temperature 11 

7. Effect of Color on Soil Temperature 12 

8. Effect of Evaporation on Soil Temperature 13 

9. Per Cent, of Air in Soils 14 

30. Separation of Sand, Silt and Clay in Soils 14 

11. Water Holding Capacity of Soils 15 

12. Effect of Humus on Water Holding Capacity of 

Soils *. . . . 16 

13. Effect of Mulches and Cultivation on Evapora- 

tion from the Soil 16 

14. Effect of Vegetable Matter on the Capillary Rise 

of Water 17 

15. Effect of a Moist Atmosphere on Dry Soils.... 17 

16. Effect of Lime on Soils 18 

17. One Effect of Humus, of Sand and of Lime, on a 

Clay Soil 19 

18. Determination of the Specific Gravity of Soils. . 19 

19. Determination of the Apparent Specific Gravity 

of Soils 20 

PART II. CHEMICAL PROPERTIES OF SOILS. 
SOIL ANALYSIS. 

20. Acids, Alkalis and Salts 21 

21. Preparation of Potash 22 

22. Preparation of Crude Phosphoric Acid 22 

23. Alkali Soils 23 

24. Gypsum Treatment for Black Alkali 25 

25. Acid Soils and How to Correct Them 25 

26. Directions for Obtaining Soil Samples 27 



CONTENTS. 5 

Page. 

27. Determination of Nitrogen 28 

28. Determination of Phosphoric Acid 29 

29. Determination of Lime 30 

30. Determination of Alkali 31 

PART III. CHEMISTRY OF PLANTS. 

31. Moisture in the Plant 33 

32. Composition of Dry Matter of Plants 33 

33. Composition of Plant Ash 34 

34. Nitrogen in Plants 36 

35. Plant Nutrition 36 

36. Nitrogen in Nodules. 39 

37. Tests for Principal Classes of Plant Compounds. . 40 

38. Occurrence and Extracting of Starch 41 

39. Inversion of Cane Sugar 42 

40. Preparation of Glucose 42 

41. Essential Oil From Plants 43 

42. Extraction of Proteids 43 

43. Extraction and Decomposition of Chlorophyll. . 44 

44. Determination of Oil in Flaxseed 44 

45. Absorption of Manure by the Soil 45 

46. Fertilizer Field Tests 45 

PART IV. AGRICULTURAL BOTANY AND PLANT 
PROPAGATION. 

47. Conditions Necessary for Germination... 47 

48. Purity of Seed and Germination Test 17 

49. Plump and Shrunken Seeds 49 

50. Depth of Germination 49 

51. Osmosis 50 

52. The Work of Leaves 51 

53. Study of the Characters of Barley 52 

54. Outline for Describing Grasses 58 

55. Identification of Clover and Grass Seeds 59 

56. Cuttings and Their Use in Propagation 60 

57. Establishing a Deciduous Orchard 62 

58. Grafting 65 

59. Budding 69 



6 CONTENTS. 

Page 

60. Laying out an Orchard 72 

61. How to Plant a Tree 73 

62. Propagation of the Grape 74 

63. Propagation of the Orange 77 

64. Pruning Fruit Trees, Vines and Bushes 78 

65. Structure and Nature of Fungi 81 

66. Structure and Nature of Bacteria 81 

PART V. ENEMIES OF CROPS. 

67. Apple Scab 83 

68. Fire Blight or Pear Blight 85 

69. The Mouth-parts of Insects 88 

PART VI. TESTING MILK AND ITS PRODUCTS. 

70. Experiments With Milk 94 

71. Analysis of Milk 95 

72. Test for Mineral Salts in the Ash of Milk 97 

73. Calibration or Correction of Glassware 98 

74. Determination of the Specific Gravity or Strength 

of Sulphuric Acid 99 

75. The Babcock Test of Milk 100 

76. The Babcock Test of Cream 103 

77. The Babcock Test of Skim Milk 104 

78. The Lactometer and Its Application 105 

79. Testing the Acidity or Sourness of Milk and 

Cream 107 

80. Calculation of the Percentage of Milk Solids 107 

81. Test for Physical Adulteration of Milk 108 

82. Test for Chemical Adulteration of Milk 109 

83. Determination of Moisture in Butter 110 

84. Determination of Salt in Butter 112 

85. Determination of Per Cent. Fat in Ice-cream. . .112 

86. Standardization of Milk and of Cream 113 



MANUAL OF GENERAL AGRICULTURE. 7 

PART I. PHYSICAL PROPERTIES OF SOILS. 

1. HOW SOILS ARE FORMED. (FIELD EXERCISE.) 

(a) Work of Atmosphere. — 1. Note any rocks worn 
away by the friction of wind or sand through the action 
of the wind. Note any rocks kept exposed to other at- 
mospheric agencies through the action of the wind; note 
any wind-bloAvn soil; any wind-blown water. 

2. Note any evidences of chemical action; oxida- 
tion; action of carbon dioxid; "rotten rock." Make a 
drawing showing successive stages of disintegration from 
solid rock to soil. 

(b) Work of Water. — 1. Note any evidences of its 
solvent power. Fill a small bottle with clear water from 
a spring or brook and when you return to the laboratory 
evaporate a few drops of it on a piece of glass or in a test 
tube, and see if there is any residue ; explain. 

2. Disintegrating Power of Water. — Note evidences 
of the washing out of loose material, and of cutting 
power of the water; of the abrasion caused by gravel, 
pebbles and stones. 

3. Transporting Power of Water. — Why is one 
stream clear, and another muddy? Note any sand or 
soil dropped by water. 

4. Note evidences of assorting power of water. 
Draw a section of the bank of a stream, showing stratifi- 
cation. 

5. Note evidences of under-ground streams, of land- 
slides, and describe and explain. 

2. TAKING SOIL SAMPLES. (FIELD EXERCISE.) 

Materials: Spade, paid, two one quart fruit jars, 
or two bottles with corks. 

Select a spot for sampling and remove any leaves 
and twigs from the surface. Dig into the cleared space 
a V-shaped hole, with one side of the V perpendicular. 
On the perpendicular side measure the depth to the 
change in color, which indicates the division between sur- 
face soil and subsoil. With the spade shave thin slices 
from the perpendicular side to the depth of the surface 



8 MANUAL OF GENERAL AGRICULTURE. 

soil, collecting the soil in a pail until you have about a 
quart. If there is no marked line between soil and sub- 
soil, sample to a depth of one foot. 

Without filling up the hole go to at least one other 
part of the field and in a similar manner obtain another 
sample, place in the pail with the first sample and mix 
thoroughly. Save about a quart as a sample of the field, 
and keep air-tight to prevent loss by evaporation. 

Continue digging to the depth of about one foot be- 
low the surface soil and collect a sample of subsoil by 
shaving thin slices as before and placing in the pail. Fill 
up the hole. Return to the original hole and obtain a 
sample of subsoil, mix the two subsoils and keep air-tight 
as was done with the surface soil. 

3. MICROSCOPICAL EXAMINATION OF SOIL 
PARTICLES. 

Materials: Compound microscope, sand, loam or silt, 
clay soil, or clay. 

Place a few grains of sand on a glass slide and ex- 
amine with low power of a microscope. 

Make drawings of several of the particles and de- 
scribe them, with reference to color; shape (angular, 
rounded, or irregular) ; simple or compound (joined to- 
gether) ; coarse, medium or fine. 

Mix loam or silt with a little water and examine a 
drop, using medium power. Draw and describe as above. 

Mix clay soil with water and examine a drop of the 
slightly muddy water using the high power. Notice that 
the soil particles are really minute rocks and humus. 
Find dark particles of humus. Find flocculated particles 
of clay, i.e. a number of particles united to form a com- 
pound particle. Draw and describe. Keeping a clay soil 
in good condition is largely a matter of keeping the par- 
ticles thus flocculated or united into small crumbs. 



MANUAL OF GENERAL AGRICULTURE. 



4. DETERMINATION OF TOTAL MOISTURE IN 
THE SOIL. 

Materials: Pour tin pans, sheet iron drying oven*, 
samples collected in Exercise 2. 

Number, mark with your initials and accurately 
weigh four pans. Record weights in your note book. 
Run all your experiments in duplicate for the sake of 
greater accuracy. 

Place in pans 1. and 2, 50 grams of surface soil, and 
in pans 3 and 4, 50 grams of subsoil. Put them in the dry- 
ing oven for at least five hours at a temperature of 100 
to 110 degrees centigrade. Cool to room temperature 
and weigh at once. The loss in weight represents the 
total moisture content of the soil. 

Tabulate the results as follows : 

TOTAL MOISTURE IN SOILS. 



Kind of 
Soil 


Pan 
No. 


Wt. of 
Pan 


Wt. of 
Soil 


Wt. of 
Dry Soil 


Loss of 
Weight 


Per Cent 
Moisture 




1 




50g. 










2 












Avg. 














Kind of 
Soil 
















3 














4 












Avg. 















Questions: 1. What were the weather conditions 
at the time of taking the samples? 2. Approximately, 
when was the last heavy rain? 3. Does the soil or sub- 
soil have the most moisture? Why? 

*A better oven is of copper set on a strong iron frame. It 
should be about 10 in. high, 10 in. deep, and 12 in. wide. The 
oven is provided with a centigrade thermometer and has a vent 
for the escape of moisture. It costs approximately eight dollars. 
As it is needed throughout the entire course, it is advisable to 
obtain one. 



10 MANUAL OF GENEEAL AGKICULTUEE. 

5. CAPILLARITY. 

rnn^f^*!"^^^' ^^-^^^ ^""^^^ ^'""^'"^^ internal diameters 

mg dish, alcohol or kerosene. Soil and subsoil collected 
m Exercise 2 For (d), 4 glass tubes at least 4 ft. long 
and of any diameter up to one inch, the larger the 
bett^er, pan, sand, sandy soil, loam, clay, small cloth and 

(a) Place the ends of the tubes side by side in a 
pan of water. Describe what takes place in the tubes 
1. Does the water rise on the inside. of each tube or does 
It rise on both the inside and outside ? 2. If two tubes 
are placed side by side and as close together as possible, 
what effect has this on the rise of water between them? 

(b) Into a small wide mouth bottle or evaporating 
dish, pour alcohol or kerosene until it stands about Hm 
deep. Fill the bottle with dry sand or finely divided 
air-dry soil and press down firmly. Let stand for about 
it) minutes, then apply a lighted match. Result? What 
does this show? This experiment represents accurately 
the capillary rise of water in soils to replace that used by 
the plant or that lost by evaporation. 

(c) Number and weigh four pans, and place in each 
o± two 50 grams of soil, and in each of the remaining 
two 50 grams of subsoil. With a pestle or glass rod 
break up all lumps, at the same time spreading the soil 
evenly on the bottom of the pans. Set aside and leave 
undisturbed until the next laboratory period Weigh 
again and continue to weigh at each successive period 
until the weights become constant. Compute the per- 
centage of capillary moisture on the basis of water free 
soil as found in Exercise 4. The difference between the 
total moisture and the amount of capillary moisture 
represents the hygroscopic moisture of soil. Calculate 
the per cent hygroscopic moisture in the samples under 
consideration. 

(d) Close one end of each tube using a piece of 
cloth and tying with a string. Fill the tubes with finely 



MANUAL OF GENEEAL AGEICULTUEE. 11 

divided air-dry sand, sandy loam, loam and clay. Do not 
separate the coarse and fine particles. Compact the soil 
by letting the tubes drop onto a book, taking care to 
let the tubes drop the same number of times and the same 
distance. Support the tubes so that the ends dip about 
one inch in water in the bottom of a pan. Observe the 
height to which the water has risen at the end of 1 hr., 
2 hr., 4 hr., 6 hr.. at the next meeting of the class, and 
at each meeting thereafter for two weeks or more. Keep 
a paper by each tube showing 1, the height of the mois- 
ture, 2, time and day of each reading. Record results 
in tabular form in your note-book. 

Questions: 1. Which tube shoAvs the most rapid 
rise? 2. At the end of an hour, which shows the greatest 
rise? 3. At the end of a wpek? 4. What effect does 
size of particles have on rapidity of movement? 

6. EFFECT OF DRAINAGE ON SOIL TEMPERATURE. 

Materials: Five-gallon oil can with one side removed, 
wooden box approximately the same dimensions. 

Fill each with the same kind of soil and apDly the 
same amount of water until drainage begins in the box. 
There will be no drainage from the can. If necessary, 
loosen a board in the bottom of the box. Let the two 
stand out of doors until the following day. Begin as early 
in the morning as possible and take thf temperatures 
hourly at depths of 1 and 3 inches until 5 P.M. Record 
results on a piece of paper left by the vessels. 

Let some pupil who lives near wet land record the 
temperatures of this land together with the temperature 
of adiacent drv land at convenient intervals some Satur- 
day. Compare his temperatures with those of the experi- 
ment. Tabulate the results. Give explanations for dif- 
ferences in temperatures. 

Question: If drainage effects the temperature, how 
may it affect a crop ? 



12 



MANUAL OF GENERAL AGRICULTURE. 



7. EFFECT OF COLOR ON SOIL TEMPERATURE. 

Materials: Two cigar boxes, soot, slaked lime, two 
thermometers, seeds. 

Place well pulverized moist soil into two cigar boxes, 
filling them about half full. In one-half of one box, bury 
twelve seeds i/o inch deep, using bean, corn, wheat, or any 
other quick germinating seeds which may be on hand. In 
the other half plant 12 seeds of some other plant. Cover 
both plantings with chalk dust, slaked lime or white ashes 
to a depth of 14 inch. 

In the same manner plant the same number and the 
same kinds of seeds in the other box, but instead of using 
light colored covering, use soot. 

Each time the class meets after the second day ob- 
serve the number of plants showing above the surface, 
keeping a record of the dates and kinds sprouted on the 
side of the box. In the morning of a clear day insert a 
thermometer into each box to about the depth of the 
sprouted seeds. After a few minutes, when the thermom- 
eters have become ad.justed to the new temperatures, take 
the readings. Continue to take the readings hourly 
throughout the day. Record the results as follows : 



DAYS TO SPROUT 



TEMPERATURE 



Light Soil 



Dark Soil 




Time 


Light 


Dark 




Soil 


Soil 


8 A.M. 






9 A.M. 






10 A.M. 






11 A.M. 






12 M. 






1P.M. 






2 P.M. 






3 P.M. 






4 P.M. 






5 P.M. 







Question : Which soil shows the higher temperature ? 
Why? 



MANUAL OF GENERAL AGRICULTURE. 



13 



8. EFFECT OF EVAPORATION ON SOIL TEMPERA- 
TURE. 

Materials: Two tomato cans, 2 thermometers, plot- 
ting paper. 

Fill two tomato cans with air-dry soil and saturate 
one with water. Bury the cans side by side in a sunny 
spot, leaving about I/2 inch of the tops above the surface. 
Insert a thermometer into each to a depth of about 1 inch. 
The following day as early as possible take the first read- 
ing and continue taking readings every hour thereafter 
until 5 P.M. On plotting paper draw a curve of tempera- 
ture for each can, using TIME and TEMPERATURE for 
the co-ordinates as shown in the diagram. 



68 
66 
64 
62 
60 
58 
56 
54 
52 
50 
48 
46 
44 
42 
40 



10 



TIME 

11 12 






14 MANUAL OF GENERAL AGRICULTUEE. 

How to plot the curve. Suppose at 8 o'clock it was 
found that the temperature of the saturated soil was 61 
degrees F., a dot should be placed half way between 60 
degrees and 62 degrees on the 8 o'clock line ; if at 9 o'clock 
the temperature was 61.5 degrees, the second dot should 
be placed Y^ of a division higher on the 9 o'clock line. 
Continue to put dots for all your temperatures. Connect 
the dots by a straight or broken line. 

9. PER CENT OF AIR IN SOILS. 

Materials: Three beakers or bottles, graduate, sand, 
clay, and loam. 

Put 25 cc. of sand in one beaker, 25 cc. of clay in the 
second, and 25 cc. of loam in the third. Fill the graduate 
to the 50 cc. mark with water and pour on to each sample 
until the water just rises to the surface. The amount of 
water required is an approximate measure of the air space, 
since the water displaces the air. Figure out the per cent 
of air space in each sample. 

Question: What effect does size of patticles have on 
total amount of air space? 

10. SEPARATION OF SAND, SILT AND CLAY IN 

SOILS. 

Materials: Tall beaker of about 500 cc. capacity, 
flask with long narrow neck, mortar, rubber pestle made 
by inserting a glass rod into a one-hole stopper. 

Weigh out exactly 20 grams of air-dry soil and place 
it in a mortar; add 12 cc. water and rub with the pestle. 
Let it settle a minute and pour off the muddy water into 
the tall beaker. Add more water to the mortar and repeat 
until the water in the mortar no longer gets muddy. The 
part remaining is coarse sand. 

With small amounts of water wash the sand from the 
mortar through a funnel into a long necked flask. 

Add water to the beaker containing muddy water 
until it is nearly filled. Stir and let stand for an hour, or 



MANUAL OF GENERAL AGRICULTURE. 15 

until the next meeting. The muddy appearance of the 
water is due to the clay, which remains in suspension. 
Siphon off without disturbing the sediment and keep both 
the siphoned portion and the residue. Fill the beaker 
again with water, stir, let settle an hour and siphon as 
before. Repeat until after standing an hour the water 
above the sediment is clear. Add the siphoned portion to 
that obtained before. Transfer the sediment to the flask 
containing the sand. Nearly fill with water and stopper 
well. Shake and invert on a ring-stand so that the neck 
is perpendicular. After the small particles have settled, 
note the different layers of sand at the bottom, to fine silt. 
Ascertain approximately by volume the percentages of 
sand, silt and clay. 

11. WATER HOLDING CAPACITY OF SOILS. 

Materials: Air-dry sand, clay, loam, three student 
lamp chimneys, cheesecloth, string. 

Tie a piece of cheesecloth over the bottom of a chim- 
ney, moisten the cloth and weigh accurately. Fill the 
chimney with dry sand and compact by dropping onto a 
book a counted number of times from the same height. 
Weigh it again and stand it in a trough containing sev- 
eral inches of water. Leave it in this position until the 
surface of the sand becomes thoroughly moist. Remove 
the tube, wipe dry, and weigh again. Cover the tube with 
cotton and set it where the water will drain away. "Weigh 
later in the day and at each meeting of the class there- 
after for at least 5 days. In the same way prepare tubes 
using clay and loam or any other soil. 

If the soil used is very dry there should be no capil- 
lary moisture, but the hygroscopic moisture is still in the 
samples, hence the results will be too low. For more 
accurate results the hygroscopic moisture should be deter- 
mined. Express your results in tabular form. 

Questions: 1. Which soil loses water more rapidly? 
2. Which takes the longest time to percolate? 



16 MANUAL OF GENERAL AGRICULTURE. 

12. EFFECT OF HUMUS ON WATER HOLDING 
CAPACITY OF SOILS. 

Materials: Three tin cans, dry well-rotted manure. 

Perforate the bottoms of three tin cans. Place a piece 
of cheesecloth on the bottom of each and weigh, recording 
the weights on the outside of each. Place in one 95 grams 
of sand, and 5 grams of well-rotted manure ; into another 
85 grams of sand and 15 grams well-rotted manure ; into 
the third 75 grams sand and 25 grams well-rotted manure. 
Saturate each with water and weigh immediately. Write 
results in each case as follows : 

Sand containing 5% organic matter retained — % 
moisture, etc. 

13. EFFECT OF MULCHES AND CULTIVATION ON 
EVAPORATION FROM THE SOIL. 

Materials: As indicated in exercise. 

Secure three five-gallon oil cans and cut them in half 
with a can opener. In case the upper half of any one can- 
not be made water-tight another must be used. Place an 
inch of gravel in each. Place in the corner of each a stu- 
dent lamp chimney. 

Fill each can with soil to within two inches of the 
top, slightly compacting the soil. Number the cans from 
one to six. Cover the soil in number five with one inch of 
sand. Cover number six with one inch of stable manure. 

Weigh each can and record its weight. Bury the 
cans in an open place until the surfaces inside and out are 
on the same level. Place them in a row according to num- 
bers and about two feet apart. Pour into each chimney 
a measured amount of water, allowing time for the soil to 
absorb it. When the cans without a mulch show damp- 
ness on top discontinue. Continue the experiment as fol- 
lows: 

No. 1, check, let alone. 

No. 2, cultivate one inch deep once a week. 

No. 3, cultivate two inches deep once a week. 

No. 4, cultivate three inches deep once a week. 

No. 5, let alone. No. 6, let alone. 



MANUAL OF GENEEAL AGEICULTUEE. 17 

Continue the experiment at least six weeks, adding 
measured quantities of water to the cans as they need it 
to keep the surfaces in good condition for crop growth. 
At the end of the required time dig up the cans, wipe the 
outsides clean and weigh. Add to the original weight of 
each can of soil, the weight of the water added, and sub- 
tract from the result the last weight of the can. The dif- 
ference represents the amount of water evaporated. Tab- 
ulate the results. 

Questions: How may a farmer obtain an artificial 
mulch ? A natural mulch ? 

14. EFFECT OF VEGETABLE MATTER ON THE CAP- 

ILLARY RISE OF WATER. 

Materials: Air-dry soil, sawdust, well rotted ma- 
nure, tubes as indicated in experiment. 

Obtain three glass tubes about an inch in diameter 
and two feet long. Close the ends of each by means of 
cheesecloth firmly tied on. Fill one tube with well pulver- 
ized air-dry soil and compact slightly. Into a second tube 
place the same kind of soil to the depth of one-half its 
length, and then place a two-inch layer of sawdust, and 
finally fill to the top with soil and compact as above. In 
the third tube use finely divided well-rotted manure in 
place of sawdust. Place the tubes so that the lower ends 
stand about an inch deep in water. At the next labora- 
tory period notice the rise of capillary water. Leave for 
another laboratory period, at which time write up the ex- 
periment and put away the apparatus. Assuming that the 
crop roots go below the straw or manure plowed under, 
state the effect of plowing under a large amount of straw 
or poorly rotted manure. 

15. EFFECT OF A MOIST ATMOSPHERE ON DRY 

SOILS. 

Materials: Sand, clay, loam, 3 fruit jars, 3 small 
receptacles to hold water and small enough to go into the 
jars, scales. 

Place 100 grams of air-dry sand in an accurately 
weighed fruit jar. Place in the jar a small receptacle con- 



18 MANUAL OF GENEEAL AGEICULTUEE. 

taining water. Tightly close the fruit jar and set in the 
sun. Repeat, using clay and loam. Weigh at each labora- 
tory meeting thereafter until the weight becomes constant. 
Remove the receptacle at each weighing. 

Calculate the amount of moisture absorbed in each 
case. These amounts are not the total moisture since the 
hygroscopic moisture was always present. 

Questions: 1. Which class of soils absorb the larg- 
est amount of moisture, and why? 2. If soil absorbs so 
little moisture from a saturated atmosphere ; why do 
wilted plants "freshen" on a foggy morning? 

16. EFFECT OF LIME ON SOILS. 

Materials: Clay or clay soil, 2 cigar boxes, slaked 
lime. 

Prepare four moulds one inch in width and the length 
of the width of the cigar box. Use pieces of one cigar box 
for the partitions in the other, thus having the four 
moulds in one box. Weigh out four 100 gr. samples of 
clay soil and add the following amounts of well-pulverized 
slaked lime : 

No. 1, add none. 

No. 2, add one gram. 

No. 3, add five grams. 

No. 4, add ten grams. 

Mix each sample thoroughly in a pan, then add just 
enough water to make the soil plastic. Mould each sam- 
ple into a form of a stick by compressing the moist clay in 
the moulds. Leave in the sun at least a week, or bake in 
an oven until thoroughly dry. Remove the sticks and 
determine the weight necessary to break each in the fol- 
lowing manner : 

Rest the ends of a stick of clay upon supports and sus- 
pend from its center a bucket into which sand is slowly 
poured. 

Tabulate the results. 

Questions: 1. How does lime effect the tenacity of 
clay? 2. What effect on the physical condition of clay 
has lime? 



MANUAL OF GENERAL AGEICULTURE. 19 

17. ONE EFFECT OF HUMUS, OF SAND, AND OF 

LIME, ON A CLAY SOIL. 

Materials: Four pans, clay, slaked lime, sand. 

Fill four pans i/4 Ml of clay and treat as follows : 

To the first add enough water to saturate the clay. 
Make a note of the amount of water used. 

To the second add about V2 its volume of humus or 
fine, dry, well-rotted manure, and the same amount of 
water as before. 

To the thir 
water, the same as before. 

To the fourth add i/^ its volume of sand and the same 
amount of water as before. Make each into a ball and set 
aside to dry. In a few days examine and see which one 
can be more easily pulverized with the fingers. 

Questions: 1. State the conclusions as to the value 
of humus, sand, and lime on a clay soil as shown in this 
experiment. 2. What causes a clay soil to bake. 3. 
How can the baking of a clay soil be prevented? 

18. DETERMINATION OF THE SPECIFIC GRAVITY 

OF SOILS. 

Materials: Graduated cylinder (25 cc. or 50 cc), 
sand, clay and loam soils. 

In this experiment we are to compare the weights of 
different soils with the weights of equal volumes of water. 
Ascertain the weight of 10 cc. of water. Place exactly 
10 cc. of water in the cylinder, reading to the top of the 
column but not including the crescent formed on the sur- 
face of the column. This water crescent is called the "men- 
iscus." Pour 10 grams of accurately-weighed sand which 
has been dried to a constant weight into the water. Shake 
to expel the air. Take the reading as before, not includ- 
ing the meniscus. Subtract 10 from this reading, and the 
remainder is the volume of water displaced by the sand. 
Determine the weight of displaced w^ater and calculate the 
specific gravity according to the following formula: 

Wt. S. 
Sp.= 

Wt. w. 



20 MANUAL OF GENERAL AGRICULTURE. 

in which Sp.^=specific gravity, "Wt. S.=weight of sand or 
soil, and Wt. 'W.=weight of water displaced. Calculate 
the specific gravity of clay and loan soils.* 

Questions: 1. What is specific gravity? 2. Why 
is it necessary to use water-free soils? 3. How does the 
amount of humus affect the specific gravity? 

The specific gravity of the material which forms the 
great bulk of most soils is about 2.6. But the soil is not a 
solid mass. It is composed of spherical particles which 
touch each other at different points. About 50% of a cul- 
tivated soil is air-space. Hence this air space reduces the 
weight of a volume of soil much below the specific grav- 
ity of its constituents. In this experiment we really found 
the specific gravity of the constituents, which is termed 
"real specific gravity." In the following experiment we 
are to determine the specific gravity, including air-space, 
which is termed "apparent specific gravitj^" 

19. DETERMINATION OF APPARENT SPECIFIC 
GRAVITY OF SOILS. 

Materials: Same as in last experiment. 
In this experiment we are to determine the ratio of 
unit weight to unit volume of different soils. 

Pour into a dry cylinder 10 cc. water-free sand. 
Weigh the sand. Having already determined the weight 
of 10 cc. water calculate the apparent specific gravity 
according to the following formula : 

V. S. 

Sp.= 

V. Wt. w. 
Wt. S.=weight of soil (i.e., weight of 10 cc. soil), V. Wt. 
W.^weight of water (i. e., weight of 10 cc. water). 

Questions: 1. What influence have stones upon the 
apparent specific gravity? 2. What influence has plow- 

*In general when cubic centimeters and grams are used the 
specific gravity of a body is found by the formula: 

Wt. body. 

Sp. Gr. of Body= 

Vol. body. 



MANUAL OF GENERAL AGRICULTURE. 21 

ing upon apparent specific gravity? 3. The apparent 
specific gravity of soils in the field may be taken as an 
indication of the tilth of soils. Why? 

PART II— CHEMICAL PROPERTIES OF SOILS. 
SOIL ANALYSIS. 

If you have talTen or are now taking chemistry pro- 
ceed at once with Exercise 20. If you have not studied 
chemistry, obtain some chemistry manual and perform the 
following experiments, as therein described : 

(1) Preparation of Oxygen. 

(2) Preparation of Hydrogen. 

(3) Preparation of Carbon dioxid. 

(4) Preparation of Nitrogen. 

The teacher should give a demonstration on labora- 
tory manipulation to students unfamiliar with chemistry. 
See any chemistry manual. 

20. ACIDS, ALKALIS, AND SALTS. 

Materials: Sulphuric acid, nitric acid, vinegar, red 
and blue litmus paper, any fruit at hand, sodium and pot- 
assium hydroxid, hydrochloric acid, evaporating dish. 

(a) Illustration and test for acids : Add a few 
drops of sulphuric acid to half a tumbler of water. Add 
drop by drop, tasting each time until the flavor can be 
distinguished. Do the same with nitric acid. 

Compare the taste of each with that of vinegar. Put 
red and blue litmus paper into the three substances used 
above. Result? This is a sure test for acids. Test the 
juice of any fruit at hand. Result? 

(b) Illustrations and test for alkalis. Dissolve a 
small piece of sodium hydroxid (caustic soda) and another 
small piece of potassium hydroxid (caustic potash), each 
in about 20 cc. of water. How does each solution feel? 
Test with both kinds of litmus paper. Result? 

Dip your finger into each solution and cautiously 
taste. This bitter taste, soapy feeling, and alkalin reac- 
tion, are the most characteristic properties of alkalis. 



22 MANUAL OP GENEEAL AGEICULTUEE. 

(c) Illustration and test for a salt. Pour out 10 cc. 
of hydrochloric acid into an evaporating dish and add an 
equal volume (10 cc.) of water. Add sodium hydroxid 
made in (b) until the solution is neutralized; i. e., until 
neither shade of litmus is changed in the solution. Evap- 
orate to dryness by heating. Watch the evaporating 
toward the end and if spattering is too vigorous remove 
the flame a moment. When evaporation is complete re- 
move the salt and add a little water. 

Note the taste and action on litmus. This is a com- 
mon table salt (sodium chlorid). 

Questions: 1. Name three classes of chemical sub- 
stances and in tabular form give their characteristic prop- 
erties as indicated in this experiment. 2. What is meant 
by a neutral substance? 

21. PREPARATION OF POTASH. 

Materials: Wood ashes, pan, evaporating dish. 

Potash is easily prepared from wood ashes. Place 
wood ashes into a pan, filling it about one-third full. Pour 
in water until the pan is about two-thirds full and stir 
vigorously for about two minutes, in order to dissolve the 
potash in the ashes. When the ashes have settled pour 
off the clear liquid and test with litmus paper. Result? 
Potash is one of the alkalis, which always have this effect 
upon litmus. Notice the soapy feel and the bitter taste, 

22. PREPARATION OF CRUDE PHOSPHORIC ACID. 

Materials: Bones, mortar and pestle, red and blue 
litmus paper, sulphuric acid, stirring rod, beaker, filter 
and filter paper, nitric acid, test tube, ammonium molyb- 
date.* 

Obtain some bones of any kind and burn them until 
white. This white substance is for the most part a com- 
bination of phosphoric acid and lime. To remove the 
lime, take about 10 gr. of burned bone and pulverize in a 
mortar, transfer to a beaker, add 50 cc. of water and 5 cc. 
of sulphuric acid and stir with a stirring rod a few min- 

*For the preparation of ammonium molybdate see page 28. 



MANUAL OF GENERAL AGRICULTURE. 23 

utes. The lime will combine with the sulphuric acid and 
leave the phosphoric acid in solution. By merely testing 
the solution with litmus paper does not prove the presence 
of phosphoric acid, even if the blue does turn red, since 
we have added sulphuric acid and some of this may not 
have been removed by combining with the lime. Hence 
we must use a special test for phosphoric acid. Filter and 
to ^ of a test tube of the filtered liquid (filtrate) add 3 
or 4 c.c. of nitric acid and heat until it just begins to boil. 
Add 1/4 test tube of ammonium molybdate. A yellowish 
color proves the presence of phosphoric acid. 

As a control repeat the experiment, using 10 grams 
of sand instead of 10 grams of bone. Upon the addition 
of ammonium molybdate does the yellowish color appear ? 

23. ALKALI SOILS. 

Materials: Three tomato cans, small pan, 3 evapo- 
rating dishes, sodium carbonate, sodium chlorid, sodium 
sulphate, hydrochloric acid. 

Among the injurious constituents of many soils of 
arid regions are certain salts collectively known as "al- 
kali. ' ' Whenever the rainfall is scant they are not leached 
out of the soil as fast as formed and so accumulate. As 
the rain water evaporates they are left on the surface, 
where they form a white deposit known as "white alka- 
li." However, there is also a black alkali formed by 
another salt, sodium carbonate. This is the worst form of 
all since it combines with the humus or organic matter of 
the soil to form a black mass, and also corrodes the plant 
just at the surface of the soil and kills it. Glauber's salt 
or sodium sulphate, together with common salt or sodium 
chlorid, and some others, form white alkali which is much 
less injurious than "black alkali." 

Obtain enough soil to fill the cans and divide it into 
three parts. Put one part into a can untreated. Put an- 
other part into the pan. Add 15 grams of powdered sodium 
carbonate and mix thoroughly, then transfer to another 
can. To the last part add 5 grams each of sodium chlorid and 



24 MANUAL OF GENERAL AGRICULTURE. 

sodium sulphate, mix thoroughly and place in the third can. 
Saturate each, including the first and compact the surface 
of the soil. Place the cans in a warm place for a week. 
The first can serves as a check. At the end of the week 
what is the difference in the appearance of the surface of 
the soil in the three cans? Sodium carbonate though 
white, acted chemically with the humus in the soil and 
formed the black substance which, as the water evapo- 
rated, was left on the surface, hence the name "black 
alkali." The chemicals in the third can did not act chem- 
ically, hence came to the surface forming the "white al- 
kali." 

Again thoroughly wet the soils, adding only a little 
water at a time so that the alkali may be washed down 
into the soil as it dissolves. Beginning as soon as the soils 
are in condition to work, cultivate the cans to the depth 
of an inch every day for a week. Why does the alkali not 
come to the surface again? 

Perforate the bottoms of the cans with a nail. Place 
each in a separate pan and add water a little at a time 
until about a pint of dram water is collected from each 
can. Again pack the soil surface and place the cans in a 
warm place for two or three days. J^ilter about 100 c.c. 
portions of each of the drainage waters into separate evap- 
orating dishes and evaporate to dryness. Is there as much 
residue in the first sample as there is in the second and 
third? "With a stirring rod taste the first residue. Add 
a few drops of dilute hydrochloric acid to the second resi- 
due. An effervescence (frothing) shows carbonates pres- 
ent. Try the first residue in the same way. Is the result 
the same? Taste the third residue. Is it salty? Does it 
taste like the first? Have the alkalis been washed from 
the soil ? After the cans have stood for two or three days 
examine their surfaces. Do they show alkali as before? 
Draw conclusions from this exercise as to the nature of 
alkali and methods of ridding the land of it. 



MANUAL OF GENEEAL AGEICULTUEE. 25 

24. GYPSUM TREATMENT FOR BLACK ALKALI. 

Materials: A tomato can, gypsum, sodium carbonate. 

Prepare a can of the same kind of soil as in the last 
experiment. Weigh out 15 grams each of sodium carbonate 
and gypsum (land plaster), powder each thoroughly and 
mix them with the soil before placing it in the can, add wa- 
ter to the soil slowly until it is saturated. Compact as in 
the last experiment. Place in a warm place for two days 
and note the incrustation. Is it " black alkali, ' ' or has the 
gypsum changed it? How does the residue compare with 
that in the third can in the last experiment? If the ma- 
terials have been well mixed the sodium carbonate will 
have acted with the calcium sulphate (gypsum) andformed 
insoluble calcium carbonate (limestone) and sodium sul- 
phate one of the compounds in "white alkali." In this 
manner the very harmful "black alkali" can be changed 
to much less dangerous white variety. 

Besides containing harmful minerals, most alkali soils 
are rich in soluble plant food such as nitrates and potas- 
sium compounds. 

25. ACID SOILS AND HOW TO CORRECT THEM. 

An acid soil, litmus paper, evaporating dish, wood 
ashes or slaked lime, pan. 

Not only do we have alkali soil, but to a limited ex- 
tent in the West we have soils that are acid. They are 
usually spoken of as sour soils. Some plants, notably 
clover and alfalfa, will not thrive in such soils because 
the soil bacteria are hindered by the acid present. 

Obtain some such soil or soils from tule land, poorly 
drained clay soil, and soil from the school yard and test 
as follows : Boil a sample a few minutes in a small quan- 
tity of distilled water and allow the soil to settle. 

Place in the dish both kinds of litmus paper. Leave 
the paper for several minutes as the soil may be nearly 
neutral, i. e., neither acid Or alkalin. Examine the lit- 
mus and compare each with the original paper. 

Stir into a soil known to be alkalin a small handful 
of slaked lime or wood ashes and test with litmus paper 



26 MANUAL OF GENEEAL AGRICULTURE. 

to determine when enough has been used to make it neu- 
tral. Use distilled water. What might be applied to an 
acid soil ? As in the ease of alkali, draining is an effectual 
remedy. 

SOIL ANALYSIS. 

There are in the earth's crust about eighty simple 
substances called elements. Of these only ten are neces- 
sary for plant growth. 

They are nitrogen, phosphorus, potassium, calcium, 
iron, surphur, magnesium, carbon, oxygen and hydrogen. 
In addition to these, sodium, silicon, chlorin and alumi- 
num are found in many plants, but are not essential to 
plant growth. None of the above elements are found in 
the plant or in the soil in the elemental form, but are 
always in combination with other elements to form com- 
pounds. 

Carbon is derived from the carbon dioxid of the air ; 
hydrogen and oxygen from the water taken up by 
plants, and the others from the soil. Of the soil elements 
potassium, phosphorus and nitrogen, and sometimes cal- 
cium, are used by plants to a much greater extent than 
the others. In fact, if the soil is well supplied with these 
four, so far as plant food is concerned, it may be consid- 
ered a rich soil. For this reason in a short analysis of soils 
the amounts of other elements are never considered. 

The manner in which these four most important ele- 
ments exist in the soil is : nitrogen as humus (vegetable 
mould), phosphorus in phosphoric acid, potassium in pot- 
ash as in leached wood ashes which by the removal of im- 
purities furnish potassium carbonate, and calcium as lime. 

The soil-humus is the chief depository of soil nitrogen 
and the main source from which plants receive their sup- 
ply. True, the air about us is composed of four-fifths 
nitrogen, but abundant evidence shows that plants cannot 
draw from this bountiful supply. For the most part, 
humus is derived from decayed vegetable matter, and as 
there is not a rank vegetation in the arid regions, it fol- 
lows that the humus content is one of prime importance 



MANUAL OF GENERAL AGRICULTURE. 27 

in many parts of California and the West. The most vital 
factor in California agriculture today is the maintenance 
of humus. This may be accomplished by crop rotation 
including in the rotation a legume (pea, bean, clover, al- 
falfa, etc,,) which has the ability to obtain its supply of 
nitrogen from the air through the bacteria which this 
order of plants harbors in its roots. Humus may be di- 
rectly added to the soil in the form of manures and in 
green crops plowed under. It is customary to estimate 
approximately the nitrogen content of soils by the propor- 
tion of humus present. 

26. DIRECTIONS FOR OBTAINING SOIL SAMPLES. 

Materials: Spade or post-hole augur, sack or board 
or oilcloth, quart jar. 

From a representative part of the field from which soil 
is to be analyzed, remove the leaves and twigs from the 
surface and dig with the spade or bore with the post-hole 
augur, down to the depth of four feet. Put all spade or 
augurs-ful of soil on a clean sack or board. Mix all the soil 
thus taken out, thoroughly on the sack or board, and keep 
about a quart of this mixed soil, which will represent an 
average of four feet in the field. 

To obtain a more representative sample, several sam- 
ples may be taken in the same way from different places 
and then a quart from all of them saved. 

PREPARATION OF REAGENTS FOR SOIL ANALYSIS. 

(The following should be prepared by the teacher or some 
trusted pupil and are enough for an entire class.) 

Ten per cent solution of caustic potash. Dissolve 20 
grams of solid caustic potash (potassium hydroxid) in 200 
c.e. of water. 

Dilute hydrochloric acid. Dilute two quarts of the 
commercial acid by pouring the acid into eight quarts of 
water. 

One-half per cent solution of phosphoric acid. Dis- 



28 MANUAL OF GENERAL AGRICULTURE. 

solve one gram of solid phosphoric acid in 200 c.c. of 
water. 

Molybdate of ammonia. Add ten grams of ammo- 
nium molybdate to 25 c.c. distilled water ; then add 15 c.c. 
of strong chemically pure ammonium hydroxid and 150 
grams chemically pure nitric acid. Keep warm and if a 
yellow precipitate appears, pour off the clear liquid for 
use ; if not the liquid is ready for use. 

A saturated solution of oxalate of ammonia. Fill a 
bottle 1/4 full of ammonia oxalate, then till with water and 
allow to stand until saturated or for several hours. 

1.7% solution of nitrate of silver. Add 1.7 grams of 
silver nitrate to 100 c.c. of distilled water. 

Ten per cent solution of barium chlorid. Add 10 
grams of barium chlorid to 100 c.c. of water. 

Ten per cent solution of ammonium chlorid. Add 10 
'grams of ammonium chlorid to 100 c.c. water. 

27. DETERMINATION OF NITROGEN. 

Materials: 10% caustic potash solution, rubber 
pestle made by placing a one-hole stopper on the end of a 
stirring rod, mortar, test tube. 

Pulverize the soil with the rubber pestle. Place 7 
grams in a test tube and add 20 c.c. of caustic potash solu- 
tion. Boil from ten to fifteen seconds, then allow the 
heavier portion to settle. The humus is dissolved and the 
density of the color of the solution is an indication of ade- 
quacy or inadequacy. A dense black, non-translucent 
solution shows the presence of at least one per cent of 
humus in the soil. A deep brown translucent color indi- 
cates the presence of about one-half of one per cent of 
humus. A light brown color clearly indicates a deficiency 
of humus. 

The test tells us about the humus only, but in all ex- 
cept very arid regions the humus content is an accurate 
index of the nitrogen content, hence the test is of prac- 
tical value. 



MANUAL OF OENERAL AGRICULTURE. 29 

28. DETERMINATION OF PHOSPHORIC ACID. 

Materials: Pint of pure sand, dilute hydrochloric 
acid, stirring rod, phosphoric acid tube.* i/2% solution 
of phosphoric acid, ammonium molybdate solution, funnel, 
test tube, filter paper, pan, iron pan or iron disc, blue lit- 
mus paper, beaker, tile, millimeter rule. 

(a) First prepare a standard of comparison** by 
taking a pint of pure sand and pouring on it about three 
times its volume or three pints of dilute hydrochloric acid. 
Allow to stand for an hour or more, stirring from time to 
time with a strong stirring rod. Place in the sink and 
allow water to run through it for several hours, until 
water after being thoroughly stirred up with it, no longer 
gives any acid reaction with litmus. Dry the sand and 
take 25 grams for this experiment, saving the rest for sub- 
sequent tests. A good content of soluble*** phosphoric acid 
in the soil is one-tenth of one per cent. We will add 
this amount to the sand and make a test. To the 
25 grams of sand add 5 c.c. of a i/2% solution of phos- 
phoric acid. This gives .025 gram in 25 grams of sand or 
.1 of 1%. Take two grams of the sand which has been 
moistened with the acid and burn for five minutes on a 
red-hot iron for the purpose of removing the vegetable 
matter or humus. Place in a test tube and add 3 or 4 c.c. 
of pure nitric acid. Heat until it just begins to boil, then 
add 2 or 3 c.c. of tap water and filter into a test tube. 
"Wash out the acid by allowing 4 or 5 c.c. of water to run 
through the sand into the filtered liquid and add to the 
filtrate, its own volume of a solution of molybdate of am- 
monia. Then place the test tube in a beaker of hot water 

*These tubes can be obtained of Justinian Cairne Co., 578 Mar- 
ket St., San Francisco, California, at 40 cents each or $4.20 per 
dozen. 

**A standard of comparison is best made by taking two grams 
of a soil in which the phosphoric acid has been accurately determined, 
instead of purifying sand, etc. 

***That is, soluble in the acids used in making tests. The soil 
may contain a great deal more phosphoric acid in insoluble form, but 
this will not appear in the test and is not directly available to the 
plant. 



30 MANUAL OF GENERAL AGRICULTUEE. 

until the precipitate has come down. Pour off the clear 
liquid at the top and transfer the rest to the phosphoric 
acid tube. Suppose that the precipitate, which is 
molybdo-phosphate of ammonium, when it has settled into 
the neck of the tube forms a column one centimeter high. 
This would indicate a content of .1 of 1% of phosphoric 
acid in the soil. With a file mark the height of this col- 
umn after making sure that the test is correct either by 
comparison with tests of others or by repeated tests. 

(b) Test soil as follows : Take two grams of soil, 
burn it on a red-hot iron for five minutes or until it is light 
gray in color. Place in a test tube and add 3 or 4 c.c. 
nitric acid, then heat until it just begins to boil ; add 2 or 
3 c.c. of water and filter into a test tube. Allow 4 or 5 c.c. 
of water to run through the soil into the filtrate and add 
to the filtrate its own volume of ammonia molybdate, then 
place the test tube in a beaker of hot water until the pre- 
cipitate has come down. Pour off the clear liquid at the 
top and transfer the rest to the phosphoric acid tube. If 
the precipitate is above the standard phosphoric acid mark 
we know that the soil is well supplied with phosphoric 
acid, i. e., there is more than .1 of 1%. Use a millimeter 
rule and calculate the exact per cent. 

29. DETERMINATION OF LIME. 

Materials : Whiting, sand treated with dilute hydro- 
chloric acid, test tube, saturated solution of oxalate of am- 
monia, ammonium chlorid, file, funnel the neck of which Is 
not more than one-eighth inch in diameter and closed at 
the bottom by heating in a hot flame, filter paper, beaker, 
millimeter rule. 

(a) First prepare a standard of comparison as fol- 
lows : To exactly 25 grams of sand previously treated 
with hydrochloric acid, add a quarter of a gram of whit- 
ing, which will give a content of one per cent of carbonate 
of lime in the soil. Thoroughly mix with the sand. Place 
a gram of this sand in a test tube and add 1 c.c. chem- 
ically pure hydrochloric acid. Heat until it just begins to 
boil, then add ammonia water until a permanent precipi- 



MANUAL OF GENEEAL AGEICULTUEE. 31 

tate appears. Filter while hot, then add a drop of am- 
monium chlorid and 1 c.c. saturated solution of oxalate of 
ammonia. Transfer to the closed funnel and allow the 
precipitate of oxalate of lime to settle. Suppose the pre- 
cipitate forms a column 2 cm. high. This would indicate 
a content of 1% of carbonate of lime. "With a file mark 
the height of this column after verifying your result, 
either by comparing with tests of others, or by repeated 
tests. The height of this mark becomes the standard of 
comparison for future tests. 

(b) Test samples of soil in a similar way as follows ; 

Place one gram of soil in a test tube. Add 1 c.c. 
hydrochloric acid and heat until it just begins to boil. 
Add strong ammonia until a permanent precipitate 
appears ; filter while hot, add a drop of ammonium chlorid 
and 1 c.c. of a saturated solution of oxalate of ammonia. 

Transfer to the closed funnel and allow the precipi- 
tate to settle. Calculate the per cent of lime by using a 
millimeter rule. Our standard indicates a lime content of 
one per cent. In a clay soil 1 to 2% is about right. In a 
sandy soil three-tenths to five-tenths of one per cent is 
good. Ten to fifteen per cent is an excess in any soil. 

30. DETERMINATION OF ALKALI. 

Materials: Sand, sodium carbonate, sodium chlorid, 
sodium sulphate, filter and litmus paper, nitric acid, silver 
nitrate solution, barium chlorid, and phosphoric acid tube. 

(a) Prepare a standard of comparison as follows: 
To 20 grams of sand which has been treated with hydro- 
chloric acid, add 4 c.c. of a solution made by dissolving 
in 100 c.c. of distilled water 1 gram of sodium carbonate, 
1 gram sodium chlorid and 3.3 grams sodium sulphate. 
This gives a content in the soil of one-tenth of one per cent 
sodium carbonate, two-tenths of one per cent sodium 
chlorid (common salt), and three-tenths of one per cent 
sodium sulphate. These are all excessive and harmful 
amounts and a soil which contains as much of any is un- 
suitable for ordinary crops. 



32 MANUAL OF GENERAL AGEICULTURE. 

(b) Test the standard sample and then 20 grams 
each of several samples of alkali soils as follows : Place 
filter paper in a funnel and put the sand or soil on it ; add 
20 c.c. of water and let it leach through into a beaker, then 
divide the leachings into two equal parts. Divide one part 
into fourths, dilute three of them with one, two and three 
volumes of water respectively. 

1. Sodium Carbonate. Test the undiluted part, then 
each diluted part with red litmus paper. The rapidity 
with which the paper turns blue indicates the amount of 
black alkali or sodium carbonate. If it quickly turns deep 
blue it indicates an excessive amount ; one-tenth of one 
per cent or more. If it turns blue very slowly it indicates 
a lesser amount. Save the original samples as a standard 
of comparison for samples of soil and label each. 

2. Sodium Chlorid. Take half of the unused leach- 
ings and test for common salt as follows : Add a few 
drops of nitric acid and then a drop or two of a 1.7 per 
cent solution of silver nitrate, a white curdy precipitate 
of silver chlorid, shows an excessive amount of salt (two- 
tenths of one per cent or more) and from this we may find, 
in testing soils, all amounts down to a trace which gives 
only a slight milkiness on the addition of silver nitrate. 

3. Sodium Sulphate. Take the remainder of the leach- 
ings and test for sodium sulphate as follows : Add a few 
drops of hydrochloric acid, heat, then add a few drops of 
barium chlorid to the hot solution. Transfer to the phos- 
phoric acid tube and in the case of the prepared sand 
mark the height of the column of precipitate which is 
barium sulphate. This indicates a content of three-tenths 
of one per cent, which is an excessive and injurious 
amount. With this as a standard we may calculate the 
amount of sodium sulphate in soil samples. (Record the 
sodium sulphate mark as before, to be used as a standard.) 



MANUAL OF GENERAL AGRICULTURE. 33 

PART III— CHEMISTRY OF PLANTS. 
31. MOISTURE IN THE PLANT. 

Materials: A small pan with a capacity of 100 to 
150 c.c, a balance sensitive to 10 milligrams, drying oven, 
thermometer. 

Dry the pan and weigh it carefully. Nearly fill it 
with finely cut stems and leaves of a fresh plant that is 
growing vigorously. Weigh again. Record all weights. 
Get the weight of the plant material by the difference. 
Place the pan in the oven and keep the temperature at 100 
to 105 degrees C. for five or six hours. Cool and weigh. 
Heat in the oven again for an hour and cool and weigh. 
If the weight is constant, the material is dry. If there is 
an appreciable difference shown by the two weighings, 
repeat the heating, cooling, and weighing till a constant 
weight is shown. The total loss in weight represents the 
amount of water held mechanically in the plant. Calcu- 
late the amount in per cent of the original weight of the 
plant material. Our ordinary growing plants hold 75 to 
95% of water in this way. Save the dry material for 
Exercises 32 and 34. 

32. COMPOSITION OF DRY MATTER OF PLANTS. 

Materials: Porcelain crucible, 250 c.c. flask, wire 
triangle, iron tripod or ring stand. 

Nearly fill the crucible with dried plant material and 
heat it over the burner till the substance begins to blaze. 
Remove the burner and quickly hold over the blazing ma- 
terial a flask, nearly full of cold water and clean and dry 
on the outside. Note the condensation of water on the 
cold surface of the flask. As the material used was dry, 
this water must have been produced by the breaking up 
of the plant tissues. It consists of oxygen and hydrogen, 
two elements of plant composition. This, as well as the 
mechanically held water, was derived from the soil water, 
having risen through the roots. Remove the flask and ob- 
serve the charred mass remaining in the crucible. It is 
principally carbon derived from the air. Continue to heat 



34 MANUAL OF GENERAL AGRICULTURE. 

the crucible until there remains a light, gray colored ash. 
These ashes show the part of the plan that is derived 
from the soil. How does it compare with the X)art derived 
from the water and air (the part that has burned away) ? 
Save the plant ash for Exercise 33. 

The average plant derives about 9.0% of its weight 
from the air, 89.5% from the water and 1.5% from the 
soil. The air always supplies its portion to the plant 
without assistance of the farmer ; our California soils are 
generally quite fertile and with proper cultivation will 
usually yield their portion of the food ; but to supply the 
large amount of water that the plant soil requires, offers 
a problem that is becoming very serious, and one to which 
we are prone not to give proper consideration. 

33. COMPOSITION OF PLANT ASH. 

Materials: Evaporating dish, funnel, filters, test 
tubes, three inches of platinum wire (fine iron wire may 
be used), cobalt blue glass (or a blue glass bottle), glass 
stirring rod, concentrated hydrochloric acid, concentrated 
nitric acid, distilled water, solutions of potassium sulpho- 
cyanate, sodium phosphate, silver nitrate, barium chlorid, 
ammonium molybdate, and ammonia. 

Place in an evaporating dish about 14 gram of th3 
plant ash left from the previous exercise. Add to it 5 c.e. 
each of distilled water and concentrated hydrochloric acid 
and a few drops of concentrated nitric acid. A rapid froth- 
ing, or effervescence, when the acid is added, proves that 
carbon is a constituent of the ash. Heat the mixture to boil- 
ing and evaporate it nearly to dryness. Add 10 c.c. distilled 
water and stir well with a glass rod. The small amount 
of white insoluble matter contains the silicon of the ash. 
Filter and wash the residue on the filter with a little dis- 
tilled water and add the washings to the filtrate. To this 
add ammonia with constant stirring till the solution smells 
strongly of ammonia, and heat to boiling. Filter and 
wash the residue as above and save the filtrate and wash- 



MA.NTJAL OF GENERAL AGEICULTURE. 35 

ings to test for calcium. To the residue on the filter add 
a few drops of hydrochloric acid, and to the liquid that 
passes through add a drop of potassium sulpho-cyanate 
solution. A red color proves iron. Heat to boiling the 
filtrate saved to test for calcium and add 5 c.c. ammo- 
nium oxalate solution. A milky white precipitate shows 
calcium in the ash. Filter and wash as above and divide 
the filtrate and washings into two parts. To one part add 
slowly drop by drop 5 c.c. sodium phosphate solution. 
Add 5 c.c. strong ammonia. A white precipitate forming 
on standing (immediately if there is much magnesium) 
proves magnesium a constituent of the plant ash. Place 
the remaining half of the above solution in an evaporat- 
ing dish. Evaporate to dryness and heat to a dull redness 
if possible, or till white vapors no longer come off. Cool 
and add to the residue a drop or two of hydrochloric acid. 
Heat a platinum wire in a colorless gas flame till it gives no 
yellow color to the flame. Dip the wire into the residue 
and again heat it in the colorless flame. A bright yellow 
color imparted to the flame proves sodium. Repeat the 
above platinum wire test, observing it through a dark 
blue glass or a blue bottle that will shut out the yellow 
color. A violet color, visible only through the blue glass, 
proves potassium to be in the ash. 

To a fresh portion of about half a gram of plant ash 
add 5 c.c. each of distilled water and strong nitric acid. 
Heat to boiling, add 10 c.c. more of distilled water and 
filter. Divide the filtrate into three parts. To one part 
add 2 c.c. silver nitrate solution. A white precipitate, or 
a milkiness imparted to the solution, proves chlorin in 
the ash. To the second add 5 c.c. ammonium molybdate 
solution and heat to blood temperature. Let stand for a 
while and a yellow precipitate will prove phosphorus in 
the ash. To the last portion add 2 c.c. barium chlorid 
solution. A white precipitate or a milkiness proves sul- 
phur. 



36 MANUAL OF GENERAL AGRICULTUBEl. 

34. NITROGEN IN PLANTS. 

Materials: Hard glass test tube, one-hole stopper to 
fit test tube, glass and rubber tubing for delivery tube, 
litmus paper, test tube, soda-lime.* 

Mix a gram of the dried plant material from Exercise 
31 with ten grams soda-lime. Place the mixture in a 
hard glass test tube about an inch in diameter. Close the 
tube with the one hole stopper connected with a delivery- 
tube that dips into a test tube of distilled water in which 
is placed a few small pieces of red litmus paper. Apply 
strong heat to the hard glass test tube for four or five 
minutes or more. Ammonia is formed from the plant 
nitrogen and this passing over dissolves in the water. If 
the litmus paper turns blue it is a proof that the plant 
contained nitrogen. 

35. PLANT NUTRITION. 

Materials : Ten glass tumblers, wrapping paper, par- 
affin, large pan, easily bent wire, six vessels that will hold 
over 500 c.c. each, 100 Canadian field peas germinated in 
moist sawdust, six quarts of distilled water, 2 grams of 
calcium nitrate, 1 gram potassium nitrate, .5 gram mag- 
nesium sulphate, .5 gram potassium acid phosphate, 1 
gram sodium acid phosphate, .5 gram sodium nitrate, .5 
gram sodium chlorid, .1 gram sodium sulphate, .1 gram 
magnesium chlorid. 

For demonstrating the necessary elements for plant 
growth, water cultures are employed. A water culture 
containing the elements, nitrogen, phosphorous, potas- 
sium, calcium, magnesium, sulphur and iron, in the form 
of soluble compounds (salts) dissolved in distilled water 
will afford more or less perfect growth. This kind of 
water culture is known as a full nutrient solution. These 
seven elements, in addition to hydrogen and oxygen found 
in water, and carbon, supplied by the carbon dioxid of the 
air, are those necessary for green plants generally. 

*Soda-lime is a mixture of caustic soda and quick lime, 
obtainable in tight bottles; it forms an eager absorbent of carbon 
dioxid. 



MANUAL OF GENEEAL AGEICULTUEE. 37 

The absence of any one will be readily shown in the 
growth of the plant. As the seed contains a considerable 
amount of plant food, no marked difference in growth may 
be noted the first few days, even though one or more of 
the necessary elements be absent. Where the necessity 
of an element is to be determined it is omitted from the 
water culture and replaced by some unnecessary com- 
pound. 

For the cultures obtain 10 glass tumblers and make a 
cover of paraffined paper for each by dipping ordinary 
wrapping paper into a pan of melted paraffin. The paper 
may be held in place by a string tied around the side of 
the tumbler. Do not tie on the covers until directed. 

Thoroughly clean six vessels and make up the follow- 
ing stock nutrient solutions : 

For calcium and nitrogen use calcium nitrate, 2 grams 
in 500 c.c. distilled water. 

For potassium and nitrogen use potassium nitrate, i/^ 
gram in 500 c.c. distilled water. 

For magnesium and sulphur use magnesium sulphate, 
y^ gram in 500 c.c. distilled water. 

For potassium and phosphorous use potassium hydro- 
gen phosphate, ^2 gram in 500 c.c. distilled water. 

For potassium (in different form than above) use 
potassium chlorid, i/4 gram in 500 c.c. distilled water. 

For iron use ferric chlorid, two drops in 500 c.c. dis- 
tilled water. 

Equal quantities of the above solutions taken will 
give a full nutrient solution in proper proportions. 

Set up the following series of cultures : 

I. One culture in distilled water. 

II. One culture in tap water. 

III. One culture in full nutrient solution, (Use 40 c.c. 

each of the six solutions prepared.) 

IV. One culture in full nutrient solution minus nitrogen 

(1) For calcium nitrate substitute 40 cc. calcium 
chlorid made by dissolving .4 gram in 100 cc. dis- 
tilled water. 



38 MANUAL, OF GENEEAL AGEICULTUEE. 

(2) ^^or calcium nitrate substitute 40 ec. potassium 
clilorid made by dissolving .1 gram in 100 cc. (Save 
the remainder for V.) 

V. One culture in full nutrient solution minus phos- 

phorous. For potassium hydrogen phosphate sub- 
stitute 40 ce. potassium chlorid made in IV (2.) 

VI. One culture in full nutrient solution minus potas- 

sium. 

(1) For potassium hydrogen phosphate substitute 
40 cc. sodium hydrogen phosphate made by dis- 
solving .1 gram in 100 cc. distilled water. 
(2.) For potassium nitrate substitute 40 cc. sodium 
nitrate made by dissolving .1 gram in 100 cc. of 
distilled water. 

(3) For potassium chlorid substitute 40 cc. sodium 
chlorid made by dissolving .4 gram in 100 cc. dis- 
tilled water. 

VII. One culture in full nutrient solution minus calcium. 

For calcium nitrate substitute 40 cc. sodium ni- 
trate in the proportion .4 gram in 100 cc. distilled 
water. 

VIII. One culture in full nutrient solution minus mag- 
nesium. 

For magnesium sulphate substitute 40 cc. sodium 
sulphate made by dissolving .1 gram in 100 cc. dis- 
tilled water. 

IX. One culture in full nutrient solution minus sulphur. 

For magnesium sulphate substitute 40 cc. magne- 
sium chlorid made by dissolving ,1 gram in 100 
ce. distilled water. 

X. One culture in full nutrient solution minus iron. 

For ferric chlorid substitute 40 cc. sodium chlorid 
made by dissolving a trace in 500 cc. distilled water. 

Place the covers over each of the ten tumblers and 
tie them securely in place. Punch ten holes in each cover 



MANUAL OF GENEEAL AGEICULTUEE. 39 

large enough for the roots of the previously germinated 
Canada field peas to go through. Select 100 of the most 
vigorous plants and arrange ten in each tumbler so that 
the roots are below and tops above the covers. In about 
two weeks it will be necessary to make a wire frame to 
support the plants. Place the tumblers in a sunny place 
and allow the culture to grow four weeks. During this 
period every few days add distilled water so that the 
quantity of the solution remains about the same. 

Make notes weekly concerning the general vigor of 
the cultures. Final notes should include (1) Average 
length of tops and of roots of each culture, (2) Green 
weights of tops and of roots. 

36. NITROGEN NODULES. 

Go out and dig up (without injury to the roots) a 
specimen of as many of the following as are conveniently 
near: a bean, a pea, a clover, an alfalfa, a lupine. These 
plants all belong to the same family, "leguminosge," and 
are commonly called "legumes." Examine the roots for 
very small knots called "nodules." Also dig up the 
roots of some cereals and examine them for nodules. Do 
you find any? Draw one root system showing nodules. 

The nodules are the home of bacteria. (See Exercise 
65, first paragraph.) These minute organisms are able 
to use the free nitrogen of the soil air and combine it 
with the mineral matter of the soil to form nitrates. The 
plant cannot use free nitrogen but flourishes on the ni- 
trates which the bacteria offer in return for the home pro- 
vided by the legume. The plant satisfies its needs from 
the nitrates thus produced and any excess remains in the 
soil for future crops. This suggests a reason for crop 
-rotation practice of following a legume crop (a nitrogen 
food producer) by a cereal crop (a nitrogen food con- 
sumer.) 



40 MANUAL OF GENERAL AGRICULTURE. 

37. TEST FOR THE PRINCIPAL CLASSES OF 
PLANT COMPOUNDS. 

Materials: Knife, test tube, iodine solution*, Fehl- 
ing's solutionf, 10% solution copper sulfate, 10% solu- 
tion potassium hydroxid, evaporating dish. 

(a) Carbohydrates. Starch. Cut a small potato in 
half. Peel and cut into small slices or rub on an ordinary 
grater a small portion and collect the pieces or gratings 
in a small dish of cool water. Boil and allow the solution 
to cool. Add a drop of iodine. A deep blue color proves 
the presence of starch. To another piece of potato add 
a drop of iodine. Result? 

Sugar. Cut another piece of potato into very thin 
slices and place in a test tube. Test for grape sugar with 
Fehling's solution as follows: Measure out 2 c.c. of solu- 
tion 1, and add to it 5 c.c. of solution 2, and 3 c.c. of 
water. Add this to the test-tube containing the potato 
and boil two or three minutes. A red precipitate (sedi- 
ment) indicates the presence of grape sugar. If the red 
precipitate does not appear soon, allow the boiled solu- 
tion to stand until next laboratory period. 

There is no elementary test for cane sugar. 

(b) Proteids. Cut cross section of beans and potato 
and carefully touch the cuts with a glass rod that has 
been dipped in nitric acid. A yellow color should appear 
which will become more intensely yellow if ammonia is 
applied. Try it. This coloration is due to the action of 
the chemicals on the proteids in the substances tested. 

Optional test. Pour a small quantity of the white 
of an egg, which is a good example of protein, in an 
evaporating dish, and barely cover with a 10% solution 

*Iodin solution is prepared by dissolving potassium iodide in 
water (about one part to seventy-five of water) and adding iodine 
crystals until the solution becomes dark brown in color. 

tFehling's solution is made by dissolving 34.65 grams of 
copper sulfate in 200 c.c. of water to make solution 1. To make 
2, dissolve 173 grams of sodium potassium tartrate (Roclielle Salt) 
in 480 c.c. of a ten per cent solution of sodium hydroxid. Use as 
directed in the experiment, making up the reagent fresh when- 
ever needed. 



MANUAL OF GENEEAL AGEICULTUEE. 41 

of caustic potash (potassium hydroxid.) Warm but do 
not cook the egg. Add a few drops of a 10% solution 
of blue stone (copper sulfate) and let stand until next 
laboratory period. At first a greenish blue color appears 
and in ten or fifteen minutes a beautiful violet color proves 
the presence of proteids. 

(c) Fats and Oils. Grind a tablespoonful of oats, 
barley, or corn. If the grinding cannot be conveniently 
done use bran, flaxseed, or any ground feed. Place in a 
bottle and pour over it 15 c.c. of ether|. Stopper, shake 
well at intervals for half an hour or let stand until the 
next laboratory period. Filter the liquid into a clean 
evaporating dish and allow the ether to evaporate in the 
open air. The residue is plant fat and oil. 

38. OCCURRENCE AND EXTRACTION OF STARCH. 

Materials: Compound microscope, piece of potato, 
grater, beaker, evaporating dish, test tube holder, glass 
tube 8 in. long, lime water, ring-stand, one-hole rubber 
stopper for test tube, cheesecloth. 

(a) Examine a thin section of potato under the 
microscope. Make a careful drawing of the structure 
of the cells and granules within. Cover the section with 
a cover glass and introduce a minute trace of iodine 
solution at the edge of the cover glass. Make a shaded 
or colored (blue pencil) drawing of the object. 

(b) Clean and peel one end of a potato. Rub it on 
a grater and collect the gratings in a beaker of cold 
water. Strain through a cheesecloth and allow the cloudy 
liquid to stand until the starch settles. Pour off some of 
the liquid and evaporate some of it to dryness in an 
evaporating dish. Describe the residue. 

Heat a small portion of starch in a test tube. What 
does this show starch to contain? Take another test tube 
and fill it one-third full of lime water. Insert into the 
test tube containing the starch a one-hole rubber stopper. 
Bend a glass tube 8 inches long into a right angle, and 

JDo not place ether near a flame. 



42 MANUAL, OF GENERAL AGEICULTURE. 

insert one end into the stopper and the other end into the 
lime water, arranging the apparatus on a ring-stand. 
Gently heat the starch in the test tube. The milky .ap- 
pearance of the lime-water indicates the presence of 
carbon dioxid in starch. Test the breath for carbon 
dioxid gas by blowing through a tube into a test tube 
one-third full of clear lime water. 

Questions: 1. What two compounds does starch 
contain? 2. What three elements does starch contain? 3. 
To what class of plant compounds does starch belong, or- 
ganic or inorganic? 

39. INVERSION OF CANE SUGAR (SUCROSE). 

Materials: Cane sugar, evaporating dish, sulphuric 
acid, sand bath, Fehling's solution, calcium carbonate, fil- 
ter paper, funnel. 

There is no direct simple test for cane sugar but by 
changing the cane sugar to grape sugar we get an indirect 
test. This change is known as inversion of cane sugar. 

Place 2 grams of sugar in an evaporating dish and 
add 30 c.c. of water and 2 c.c. of sulphuric acid. Heat 
fifteen minutes on a sand bath, replacing the water lost 
by evaporation. Neutralize with calcium carbonate. De- 
termine when neutral by using litmus paper. Add more 
water for filtration if necessary. Test with Fehling's 
solution. Result ? 

Take one-tenth gram of cane sugar, dissolve in 10 c.c. 
of cold water and test with Fehling's solution. Result? 

Question: 1. What is the object of adding calcium 
carbonate ? 

40. PREPARATION OF GLUCOSE (GRAPE SUGAR) 

Materials: Evaporating dish, sand bath, starch, cal- 
cium carbonate, litmus paper, iodin solution, filter, stir- 
ring rod, Fehling's solution. 

Add 10 drops of sulphuric acid to about 35 c.c. of wa- 
ter in an evaporating dish. Heat on a sand bath until the 
boiling point is reached. Add 1 gram of pulverized starch, 
noting its appearance immediately after adding. Heat 25 



MANUAL OF GENERAL AGRICULTURE. 43 

minutes, stirring occasionally, and replacing water should 
too much evaporate. Add calcium carbonate to neutral- 
ize the sulphuric acid. Determine when neutral by using 
litmus paper. "When neutral filter and wash the residue 
with 15 c.c. of water. Test a few drops of the filtrate with 
iodin. Have the properties of the starch been destroyed? 
Evaporate the remainder in an evaporating dish to about 
10 c.c. Test for glucose or grape sugar with Fehling's 
solution. 

41. ESSENTIAL OIL FROM PLANTS. 

Materials : Tea, clover, or alfalfa, glass stoppered re- 
tort (as used in preparation of nitric acid), large test tube, 
wire gauze. 

Place 5 grams of tea into the glass stoppered retort 
and add 50 c.c. water. Place the end of the retort in a 
test tube one-third full of water. Support the apparatus 
on a ring stand, allowing the retort to rest on a wire 
gauze. Apply heat and distill 3 or 4 c.c. Observe the 
color of the distillate (in the test tube.) Is the essential 
oil from tea volatile 1 Repeat the experiment, using clover 
or alfalfa. 

42. EXTRACTION OF PROTEIDS. 

Materials: Flour, cheesecloth, pan, 10% solution of 
sodium chlorid, test tube. 

A good illustration of protein is gluten, obtained from 
wheat fiour. Mix in a pan with a glass rod 30 grams of 
flour and sufficient water to make a stiff dough and let 
stand half an hour in order that the physical properties of 
the gluten may develop. Place in a cheesecloth and wash 
in a stream of water, working the dough gently with the 
fingers. 

Continue washing until the water runs away clear, 
which indicates that all the starch has been washed out. 
The gluten remains on the cheesecloth. Treat a small por- 
tion of gluten with a 10% solution of sodium chlorid. 
Does it dissolve? 

In California there are no definite divisions between 
winter and spring wheats. But in localities where this 



44 MANUAL OF GENERAL AGRICULTURI]. 

distinction is marked, or where flour from winter and 
spring wheats can be obtained, treat a sample of each as 
indicated, and compare the two. 

43. EXTRACTION AND DECOMPOSITION OF 

CHLOROPHYLL. 

Materials: Green leaves, preferably of young grow- 
ing grass or cereal, large test tube, two small test tubes. 

Place some green leaves into a large test tube, filling 
the tube about one-third full. Pour alcohol over them 
until the test tube is about one-half full. Boil for about 
two minutes. Transfer the liquid to two small test tubes, 
pouring the same amount into each. Note the color of the 
chlorophyll extract. 

Place one solution in direct sunlight and the other in 
complete darkness. At the end of an hour and again at 
the next meeting compare the two. 

Questions: 1. What is chlorophyll? 2. What is 
the effect of light on chlorophyll? 

44. DETERMINATION OF OIL IN FLAXSEED. 

Materials: Ground flaxseed, ether or benzine, evapo- 
rating dish, filter, filter paper, ring stand. 

(a) Weigh out 25 grams of flaxseed and add 25 c.c. 
of ether or benzine.* Let stand about fifteen minutes and 
then filter into an evaporating dish. Wash the meal by 
pouring over it, a little at a time, about the same amount 
of ether or benzine. Let the liquid stand in a good draft 
until the next laboratory period or until it has lost the 
odor of the liquid used. Weigh the remaining oil (fat) 
and calculate what per cent of the ground seed was oil. 
(A small amount of fat will still be left in the residue.) 

(1) Describe the oil obtained. (2) Of what use 
would it have been to the plant? 

Optional. Oil from yolk of egg. Repeat the above 
experiment, using 10 grams of the yolk of a hard-boiled 
egg and add 10 c.c. of ether or benzine. 

*Do not bring ether or benzene near a flame. 



IMANUAL OF GENERAL AGRICULTURE. 45 

(1) Compare the appearance of this oil (fat) with 
that from flaxseed. Are the oils in flaxseed and the yolk 
of an egg volatile? 

45. ABSORPTION OF MANURE BY THE SOIL. 

Materials: A pan, a tall quart can, a large funnel, a 
beaker and quart of well rotted stable manure. 

Soak a quart of well rotted stable manure for two 
days in enough water to cover it. Perforate the bottom 
of a tall, narrow can, holding about a quart, and fill it 
with dry soil. Set it in a large funnel. Pour off the water 
from the manure and note its color. A large part of the 
fertilizing value of the manure has dissolved in the water. 
This suggests that the practice of piling manure in heaps 
and letting it lay exposed to the leaching action of the 
winter rains is a very wasteful one. Slowly pour the ma- 
nure water over the soil and let it drain through into a 
beaker. Compare the color of the drainage with that 
before adding it to the soil. Has the soil absorbed the val- 
uable part of the manure? A common practice is to pile 
a load of manure in a place, throughout the field, and scat- 
ter the piles after they have rotted all winter. Will this 
give an even distribution of the fertilizing part of the 
manure ? 

46. FERTILIZER FIELD TESTS. 

This set of tests should be carried on in co-operation 
with some progressive farmer whose farm is near the 
school. Select a field that is not yielding well. Lay out 
the field of uniform soil, or as nearly as may be, in plats 
of 2 rods or 33 feet by 4 rods or 66 feet. There will be 
one-twentieth of an acre in each plat. Put stakes at the 
corners and keep an accurate record as to treatment. 
When the soil is thoroughly prepared, and just before 
seeding, apply the fertilizers by sowing them broadcast, 
being careful that all parts of the plat receive the same 
quantity of fertilizers. The eight plats should be fertil- 
ized as follows : 



46 MANUAL OF GENERAL AGEICULTUEE. 

No. 1. No fertilizer, serving as a check. 

No. 2. 10 lbs. sulphate of potash. (Approximate 
cost 4c per lb.) 

No. 3. 20 lbs. acid phosphate. (IV2C per lb.) 

No. 4. 10 lbs. nitrate of soda, (3c per lb.) 

No. 5. 10 lbs. nitrate of soda, 20 lbs. acid phosphate. 

No. 6. 10 lbs nitrate of soda, 10 lbs. sulphate of pot- 
ash. 

No. 7. 10 lbs. sulphate of potash, 20 lbs. acid phos- 
phate. 

No. 8. , 10 lbs. nitrate of soda, 10 lbs. sulphate of 
potash, 20 lbs. acid phosphate. 

No. 9. A half ton of stable manure. 

No. 10. Special. Some fertilizer not included in the 
above but used locally as 2 lbs. land plaster (gypsum, or 
cow manure, or sheep manure, etc.) Plaster and manure 
show more marked results the second year. 

Sow all plats exactly alike with the same kind of 
seed. One of the crops ordinarily raised in the commun- 
ity, such as corn, wheat, barley, etc., should be used. If 
the class is large enough three or four set of plats as de- 
scribed above may be used, each being sowed to a differ- 
ent crop. When the crop is ripe, each plat should be 
separately cut and threshed and the yield of grain and 
straw both carefully weighed. A study of the yields of 
the plats as compared with the fertilizers applied will give 
the necessary data to determine what combination of fer- 
tilizing material will cause the field to increase its yield 
of that particular crop, and will give a partial check on 
the deficiency of the soil in any particular plant food. A 
second year of tests on the same plats will serve as a val- 
uable check on the first year's results. 

Let the students devise a series of tests to show the 
fertilizer requirements of the fruit trees in some nearby 
orchard. Fertilizers should not be applied around the 
base of the tree or much injury may be done. The feeding 
roots are spread over an area equal to or greater than that 
covered by the branches, and the fertilizer should be 



MANUAL OF GENERAL AGRICULTURE. 47 

spread accordingly. The trees should be numherpd and 
the results noted for two or three years. The fertilizers 
have little apparent effect on the trees for the first year. 

PART IV— AGRICULTURAL BOTANY AND PLANT 
PROPAGATION. 

47. CONDITIONS NECESSARY FOR GERMINATION. 

Materials: Six tomato cans, peas, or beans. 

Number the cans from 1 to 6. Fill numbers one, four 
and six with rich, moist, loamy soil. Fill number three 
with the same kind of soil, having first thoroughly air- 
dried it. Leave numbers two and five without soil. Plant 
in each of the soil-filled cans six seeds of peas or beans, to 
a depth of one inch, and press the soil firmly around the 
seed. Place the same number of seed loose in numbers two 
and five. Number one, two, four and six are to be kept 
moist throughout the experiment. Fill number five with 
water, that has been previously boiled and cooled, to keep 
out air. Place numbers one, three and five in a warm, 
light place. Place number six in a warm place, but cover 
it with dark cloth or paper to exclude the light. Keep 
number three in a refrigerator or ice box so that the tem- 
perature may be maintained near the freezing point. Ex- 
amine the cans after two or three days, and then every 
day until you can answer the following : Which of these 
conditions ; soil, moisture, warmth, air, light, are neces- 
sary for the germination of seeds? Seeds contain a very 
small amount of air. The water may also contain a small 
amount of air. Take this into account in answering the 
questions. 

48. PURITY OF SEEDS AND GERMINATION TEST. 

(a) Purity of Seeds. Materials: Three samples of 
clover seed or any small seeds used locally, chemical 
scales, three blotters of ordinary size, three pans and glass 
to cover each. 

"Weigh out 5 grams of samples of seed from each of 
three samples furnished. Spread this on a sheet of paper. 



48 



MANUAL OF GENERAL AGRICULTUEE. 



Separate into three piles: (1) Chaff, dirt, broken seed, 
etc.; (2) Sound seed; (3) Weed seed. Weigh each lot. 
Save the seed from each sample. Record results. 



Sample 


Weed 
seed, 
grams 


ChaflF, 

dirt, 

broken 

seed, 

grams 


Per cent 

of sound 

seed 


Market 

price per 

lb. 


Actual 

cost per 

lb. 


1 












2 











3 









Which gives the largest amount of seeds for the price ? 
Does this sample contain many weed seeds? Consider- 
ing price, quality and weeds seed, which sample should 
be purchased? 

(b) Germination Test. Moisten a piece of blotting 
paper and lay it in a pan. Take 100 seeds from a sam- 
ple of pure seed just as they come. Put them on the blot- 
ter and label. Moisten another piece of blotting paper and 
lay over them, and cover with glass or straw. Keep moist 
and in a moderately warm room. Do the same with the 
other samples. Examine from day to day, and remove 
the sprouted seeds from each sample. 



Sample No. 



Total 
per cent 





3 days 


4 days 


5 days 


germinated 


1 










2 










3 











The quickness Avith which the seeds start indicates 
something of their vigor. Which sample germinated 
quickest? From this and (a) fill out the following table: 



MANUAL OF GENERAL AGRICULTUEE. 



49 



Sample No. 


Market 
price per lb. 


Per cent of 
good seed 


Cost per lb. 
of good seed 




1 










2 










3 











49. PLUMP AND SHRUNKEN SEEDS. 
Materials: A box about 4 inches high, a foot wide 
and 2 feet long. Half pint sample of wheat seed and 
scales. 

(a) Calculation of Plant Food in Seeds. Weigh 100 
plump, well-formed Avheat seeds. From this weight and 
the following data compute the grams of nitrogen, phos- 
phoric acid, and potash per 1000 wheat seeds. Wheat 
contains about 2 per cent nitrogen and 90 per cent dry 
matter. The dry matter contains about 2 per cent ash, 
about 50 per cent of this ash being phosphoric acid and 
33 per cent potash. Repeat the experiment, using 100 
shrunken seeds. 

(b) Growth of Plump and Shrunken Seeds. Select 
12 plump seeds and also 12 that are shrunken. Fill the 
box with good rich, moist, loamy soil. Plant the plump 
seeds in one end and the shrunken seeds in the other. 
Keep the soil moist and warm. Examine the young plants 
from time to time as they germinate and grow. Note the 
number of plants secured from the plump seeds and from 
the shrunken seeds. Let the plants continue to grow for 
several weeks. 

Questions: Can you detect any difference in the 
hardiness of the plants and the amount of plant material 
produced by the two grades of seed? State your conclu- 
sions. 

50. DEPTH OF GERMINATION. 

Materials: Three half-gallon fruit jars, three pint 
fruit jars. 

(a) Large Seeds. — Place about IY2 inches of good 
moist soil in the bottom of each jar. Plant one with peas, 



50 MANUAL OF GENERAL AGRICULTUEE. 

one with beans, one with corn, as follows: Plant two 
seeds near together against the wall of the jar and on the 
surface of the soil. Add an inch of soil, press it down 
firmly and after turning the jar slightly to one side, 
.plant two more seeds so that they will not be directly over 
those already planted. Continue to add soil and plant 
seeds every inch up the side of the jar till near the top. 
Wrap each jar in dark cloth or paper to exclude the light, 
and set in a warm place. From day to day, remove the 
wrapping from the jars and note the growth, recovering 
them immediately. This exercise should give some idea 
of the power of different kinds of seeds to force their 
plantlets up through the soil. Note the depth of the low- 
est seed in the jars that is able to penetrate to the surface. 

(b) Small Seeds. — Kepeat (a) using the pint jars 
and planting the lowest seeds about an inch from the bot- 
toms. Use small seeds, such as radish, alfalfa, clover. 

How do the depths of germination with large seeds 
and small compare ? Give reason for this. Oil producing 
seeds contain much more food in proportion to their size 
than do the starchy seeds. 

51. OSMOSIS. 

Materials: Potato, two wide mouth glasses or beak- 
ers, glass tube 6 inches long and about 3-16 inch inside 
diameter, egg, hatpin, sealing wax, salt. 

1. Pare a potato and cut slices from it. Place some 
of these in water and some in a strong solution of salt 
made by placing a small handful of salt into a glass of 
water. Examine at the next exercise. 

2. Cement with sealing wax to the smaller end of an 
egg a piece of glass tubing about 6 inches long and about 
3-16 inch inside diameter. Clip away part of the shell 
from the larger end of the egg, place in a wide mouth bot- 
tle or small beaker full of water and then carefully pierce 
a hole through the upper end of the eggshell by pushing 
a hatpin through the glass tube. Examine at the next 
exercise. 



MANUAL OF GENERAL AGRICULTURE. 51 

In the ease of the potato the piece in water is plump 
and rigid, which shows that the water passed into the 
potato faster than the sap passed out. The piece in the 
salt solution is wilted, which shows that the salt solution 
did not pass into the potato as fast as the sap passed out. 

In the case of the egg, the water passed into the 
egg more readily than the denser egg solution passed out 
into the water. As the water passed in, the egg albumen 
was pushed up the tube by osmosis. Whenever a plant or 
an animal membrane separates two solutions, there is an 
interchange of the two. The less dense the solution, the 
more rapidly the water passes through the membrane. The 
solutions of root-hairs are more dense than the soil solu- 
tions, hence more water passes into the root than passes 
out into the soil. 

Questions: 1. What is the danger in using an ex- 
tremely strong fertilizer? 2. How does this experiment 
show that an excess of alkali in the soil often prevents 
the growth of the plant? 

52. THE WORK OF LEAVES. 

Materials: Two small watch glasses, vaseline, two 
circular disks of two pins. 

1. Transpiration. Fasten two small watch glasses, 
one on each side of a leaf of a plant growing vigorously 
out of doors. The glasses may be held in place by sealing 
the margin of each all the way around by vaseline or 
grafting wax. An hour later or at the next meeting exam- 
ine the drops of water inside of each glass. The giving 
off of moisture by the leaves is called transpiration. 

2. Light. Select some leaves on a vigorously grow- 
ing plant. Shut off the sunlight from parts of the selected 
leaves, which must be left on the plant and as little injured 
as possible, by pinning circular disks of cork loosely on 
opposite sides of each leaf. Two or three days later remove 
these leaves and the cork disks. Compare the color of the 
covered area with the color of the remainder of the leaf 
and explain. Why do most plants not do well in the 
shade of trees? 



52 MANUAL OF GENEEAL AGEICULTUEE. 

3. Oxygen Making. Place some green aquatic plant 
in a glass jar full of water in front of a sunny window at 
about 70° F. In a short time note the formation of oxy- 
gen bubbles looking silvery by reflected light. Remove to 
a dark place and after a few minutes examine by lamp 
light to see whether the rise of the bubbles still continues. 

One of the most important facts about life is the 
taking in by plants from the air of carbon dioxid, a com- 
pound composed of carbon and oxygen. The plants use 
the carbon and give off the oxygen. The process is the 
opposite in the case of animals, which Ijreathe oft' car- 
bon dioxid and breathe in oxygen. Plants by a dusty 
road side often become covered with dust. What effect 
would this have on 1, 2 and 3? 

53. STUDY OF THE CHARACTERS OF BARLEY.* 

Materials for this exercise and also for exercises 54 
and 55 may be obtained from the University of Nebraska, 
Department of Field Crops, Lincoln, Neb. For Exercise 
53, Order Lot 3. This lot contains nine barley types witli 
about 25 specimens per type. Price per lot $1.75. For 
Exercise 54, Order Lot 58. This lot contains fourteen spe- 
cies of cultivated grasses given in the exercise, together 
with one additional. Price per lot $1.75. For Exercise 55 
(a) Order Lot 59. This lot contains the seeds of eleven 
species of clovers given in the exercise with two addi- 
tional. Price per lot in 2-ounce bottles $1.50. For 55 (b) 
Order Lot 58, which contains the seeds of the fourteen spe- 
cies of cultivated grasses given in the exercise with one 
additional. Price per lot in 2-ounce bottles $1.25. One or 
more lots may be ordered, but the lots will not be broken. 

Cultivated barleys include a number of types, or 
races, and may be classified as follows: 

(1) Two-rowed barley Hordeum sativum distichon 

(2) Six-rowed barley Hordeum sativum hexastichon 

The two-rowed barleys commonly grown are charac- 
terized by their large, plump grain. In Europe these bar- 

*For exercises similar to this on corn, wheat and oats see 
"Examining and Grading Grains" by Lyon and Montgomery. 



MANUAL OF GENERAL AGRICULTURE. 



53 



leys are used almost exclusively for malting, and hence 
the name "malting barleys" has come to be generally 




Fig. 1. 



Types of barley spikes: A, two-rowed brewing barley; B, 
six-rowed hiilless barley 



applied to them. However, in America the six-rowed bar- 
leys are generally used for this purpose. 

The six-rowed barleys include the "naked," or "hull- 
less" varieties, as well as most of our common cultivated 
barleys. The six-rowed barleys are generally more pro- 
lifie than the two-rowed, and are most generally grown in 
this country. The grains of six-rowed barleys are smaller 



54 MANUAL OF GENERAL AGRICULTUEE. 

and not so plump as those of the two-rowed barleys, but 
are higher in nitrogen. 

The varieties of barley are numerous, but only a com- 
paratively few are grown in the United States. 

Carefully examine samples of each of the above types 
of barley including samples of both black and white hull- 
less barley. 

Make drawings from a spike of each type, showing 
the imbricated view. 

Note that the berry of ordinary barley is tightly in- 
closed by the flowering glume, called the "hull," while 
in huUess barleys the flowering glume and palet do not 
adhere closely and the berry is free. 

In this respect hulled barley is similar to oats, and 
hulless to wheat. 

LABORATORY STUDY OF CHARACTERS. 

Typical samples in the spike and of the threshed 
grain are provided. Carefully describe both the spike and 
grain of one or more samples of the principal types of bar- 
ley, as the two-, four-, and six-rowed barleys, and black 
and white hulless barleys. 

The characteristics are obvious enough, so that with 
a little careful comparison there should be no trouble in 
finding the proper adjective in the descriptive list. 

Use the outline for describing barleys, filling it out 
carefully. 

TERMS FOR DESCRIBING BARLEYS. 

Spike 

1 . /Two-rowed (Fig. 1, A). 1 This refers to the number of rows 
Six-rowed (Fig. 1, B). j of grain on the spike. 
Awned (Fig. 1, A). 
Partly awned (Fig. 1, B). 
Awn less. 

3. Length (inches). 
( Open (Fig. 1, A). 1 Has reference to how close or far 

4. \ Compact (Fig. 1, B). > apart the spikelets are on the 
[ Crowded. J rachis. 



MANUAL OF GENERAL AGEICULTURE. 



55 



Shape 



Tapering toward tip. 

Tapering both ways. 

, Uniform (Fig. 1, A). 
' Tip tapering (iig. 1,A). 

2. I 
Tip blunt (Fig. 1, B). 

f Base abrupt. 

3 . \ Base tapering. 

4 . Sterile spikelets, 1, 2, 3, 
Color 

Whitish. 
Yellowish. 
Yellowish brown. 
Brown. 
Black. 



When upper spikelets are appressed. 
When spikelets at both base and 
tip are more appressed than 
those at middle. 



When terminal spikelets are not 

well filled out. 
Terminal spikelets well filled out. 
Basal spikelets well filled out. 
Basal spikelets not well filled out. 



et(v 



Awns 
1. 

2. 

3. ■ 

Color 
1. ' 



Long (length 5 inches or more). 
Medium (length 3 to 5 inches). 
Short (length less than 3 inches). 



Parallel (tig. 1, B). 
Spreading (Fig. 1, A). 

Deciduous. 

Partly deciduous (Fig. 1, B). 

Persistent (Fig. 1, A). 



Whitish. 
Yellowish. 
Brownish. 
Black. 



Refers to the relative position 
of the awns to the head. 

This refers to the dropping of 
the awns at maturity. The 
awns all drop off on some 
varieties, while on others 
they are very persistent. 



Spikelet 

(This is not a spikelet in the botanical sense, but really a mesh of 
three spikelets.) 

1 . Number grains per spikelet (1, 2, 3). 

2. Number of sterile flowers. (Refers to sterile flowers in a 
spikelet.) 



Size 



1. 



Broad (Fig. 2, C). 
Medium (Fig. 2, B). 
Narrow (Fig. 2, A). 



This depends largely on the shape 
of the grain and how well it is 
developed. 
Outer Glume. (In barleys these are very narrow and pointed.) 

[ Awned (Fig. 2, B). ] The outer or empty glume should 
1. I Awn-pointed. [ not be confused with the flower- 

[ Awnless (Fig. 2, D). J ing or seed-bearing glume. 



56 



MANUAL OF GENERAL AGRICULTURE. 



Grain 



1. 



Inclosed in flower- 
ing glume. 
Free (naked). 



This is the distinguishing characteristic 
between the naked or huUess barley 
and the ordinary kind. In the latter 
the grain is so tightly inclosed that 
it is not freed in threshing. 




Fig. 2. Types of barley spikelets: A, spikelet from two-rowed 
barley; B, spikelet from six-rowed barley; C, a six-rowed hulless 
barley; D, a white hulless and awnless barley; £^ shows a barley 
spikelet torn apart. 

Hard. ] This point is most easily determined by biting or 
Medium. !■ cutting the grains and comparing with stand- 
Soft. J ard samples. 



Shape 



C Long. 

1. \ Medium. 
I Short. 

Thin. 

2. \ Medium. 
[ Plump. 



I Different varieties of barley show considerable 
! variation in size and ratio of length to diam- 
|- eter. Pick out about six typical grains to 
J examine for these points. 



M..^NUAL OF GENERAL AGRICULTURE. 



57 



Crease 

( Deep. 
1. \ Medium. 

i Full. 
Cross section 

( Horny. 
1. ] Dull. 

[ Starchy. 



Color 



Black. 

Purple. 
, Purplish. 
j Brown. 
I Yellowish. 
I Whitish. 



Cut cross sections of several typical grains. 



This point is determined by making cross sec- 
tions and examining carefully. Where only 
part of the grains show one characteristic 
and the rest some other, the per cent of each 
kiiid should be expressed. 



When black huUess barleys are fully matured 
they are purplish black in color, but when 
cut very green they are ofcen a yellowish 
white in color, with only a tinge of purple. 



Weight of 100 grains grams 

OUTLINE FOR DESCRIBING BARLEYS. 
Spike 

1 

2 

3 

4 

Shape 

1 

2 

3 : 

4 

Color 

1 

Awns 

1 

2 

3 

Color 

1 

Spikelet 

1 : 

2 

Size 

1 

Outer Glume 

1 



58 MANUAL OF GENERAL AGRICULTURE. 

Grain 

1 

2 

Shape 

1 

2 

Crease 

1 

Cross section 

1 

Color 

1 

Weight of 1 00 grains (grams) 

Question: What advantage has hulless barley? Hull 
barley ? 

54. OUTLINE FOR DESCRIBING GRASSES. 

Materials: Lens. See Exercise 53. 

The following outline is used in the study of common 
cultivated grasses. By following the outline one's at- 
tention is called to the distinguishing characteristics of 
each kind, giving not only a means of identification but 
a good knowledge of the grass. 

The stem and leaves 

Height 

Color of stem 

Color of leaves 

Number of leaves 

Head 

Awned or awnless 

Panicled, compact, or spiked 

Size (give length and diameter) 

Color of awns 

Color of chaff 

Boot 

Does it spread from rootstocks? 

Is it a sod-forming or bunch grass? 

Seeds 

Size (give average length in inches) 

Color (general color) 

General Notes 

Is seed free or inclosed in scales! 

Weight per bushel 

Amount sown per acre 

Vitality 



MANUAL OF GENEEAL AGEICULTUEE. 59 

Drawings of Seeds. Make drawing from convex side. 
Make drawing of cross section. 

Question: Give an illustration of a sod forming grass 
and a bunch forming grass. Discuss the advantage of 
each. 

55. IDENTIFICATION OF CLOVER AND GRASS 
SEEDS. 

Materials: Lens. See Exercise 53. 

There is no work which requires more careful atten- 
tion or is more valuable than the identification of grass 
and clover seeds, and separating them from their adul- 
terants. 

For examining the seeds a small lens is very use- 
ful. Use the following artificial key, which is not in- 
tended to describe the seed but simply calls attention to 
the most prominent characteristics of each variety. It 
is much better to first learn to identify by use of the 
key than by use of the drawings. 

(a) Key for Identification of Clover Seeds 

Seed free (not inclosed in pod) 
Seed bean-shaped 

Color, pinkish, % in. long Crimson Clover 

Color, mostly yellow; large seeds are kidney shaped Alfalfa 

(Turkestan alfalfa is same, but slate colored.) 

Seeds larger and more regular than in alfalfa Burr Clover 

Color, dark yellow to brown Yellow Trefoil 

Seed oval-oblong 

Color, yellow; seed notched near one end Bokhara Clover 

Seed heart-shaped 

Color, yellow to brown White Clover 

Color, dark green to black Alsike Clover 

Seed somewhat triangular 

Color, yellow to brownish Eed Clover 

Seed inclosed in pod 

Pod large and corrugated, % in- long 

Color, brown; seed, bean-shaped Sainfoin 

Pod whitish, % in. long 

Color, yellow; seed oval, notched near end 

Yellow Sweet Clover 
Pod brown, Ys in. long 

Color, dark brown, seed mottled Japan Clover 



60 MANUAL OF GENERAL AGRICULTURE. 

(&) Key for Identification of Grass Seeds 
Seeds distinctly awned 

Seed % in. or more in length 

Very hairy or pubescent, flat, thin Meadow Foxtail 

Awns attached at tip Annual Rye Grass 

Awns long, twisted, attached near base.. ..Tall Meadow Oat Grass 
Seeds less than i/4 in. long 

Small brownish seed Sheep Fescue 

Short-awned or awn-pointed 

Small, dark brown seeds, very rough near tip. .-Crested Dog's-Tail 

% in. long, smooth, light colored Wheat Grass 

1/4 in. or less in length Orchard Grass 

Awnless 

% in. long or thereabout, nerves very prominent. ...Brome Grass 
About 1/4 in. long ( Note difeerence in shape ) -Perennial Rye Grass 

light brown ] and size of rachilla ^ Meadow Fescue 

Hard, smooth seeds, about Y^ in. long 

Dark brown color Johnson Grass 

'% in. long or less 

Keel rough, sawlike Redtop 

Keel not commonly rough Kentucky Blue Grass 

Seed free from glumes, polished 

Very small, 1-32 in. in length, polished Timothy 

56. CUTTINGS AND THEIR USE IN PROPAGATION. 

The more common forms of artificial reproduction are 
by cuttings, grafting and budding. A cutting is a de- 
tached portion of a plant inserted in soil (or in water) 
for the purpose of producing a new plant. Cuttings may 
be divided into three classes: 1. Hard-wood cuttings. 2. 
Soft-wood cuttings (herbaceous). 3. Root-cuttings. 

1. Hard Wood Cuttings. A hard-wood cutting is a 
cutting from the ripened wood of a deciduous plant of the 
present or previous season's growth. The cultivated 
plants most commonly propagated by the use of hard- 
wood cuttings are grape, olive, fig, quince, currant and 
gooseberry, and many ornamental shrubs, such as privet, 
tamarisk, hydrangra, etc. 

2. Soft Wood Cuttings. This class of cuttings is ex- 
amplified in the "slips" used to increase the number of 
roses, carnations, geraniums, fuchsias, begonias, etc. Leaf 
cuttings are often employed in multiplying begonias, cacti 
and other plants having thick fleshy leaves containing a 



MANUAL or GENEEAL AGEICULTUEE. 61 

large quantity of plant food. Soft-wood cuttings are of 
little importance in agriculture. 

3. Root Cuttings. Short cuttings of roots may be 
used in the propagation of many plants, notably the horse 
radish. The roots of lippia, bermuda grass and some other 
grasses can be cut into short pieces and planted. 

Obtain some hard-wood cuttings of apple, peach, pear, 
plum, berry canes, fig, olive, quince and any others that 
are available. Get cuttings about 18 inches long and 3-8 
to 5-8 inch in diameter, using wood of the previous sea- 
son's growth. They should be obtained during the dor- 
mant period (January) or at the time of pruning. Cut 
five from each tree and tie them in separate bundles with 
the butts all one way, then label with a piece of wood. 

In order to save time and trouble we may as well ob- 
tain scions for grafting at this time and care for them in 
the same ways as described below for cuttings. A scion 
is a portion cut from a plant to be inserted upon another 
plant with the intention that it shall grow. Obtain scions 
to be grafted on year old seedlings grown as indicated in 
Exercise 56. If there are no year old seedlings to be 
grafted, no scions need be gathered, but in order to save 
time in getting started seedlings should be bought. Select 
10 scions of about the size of the seedlings to be grafted 
so that they may be easily matched, tie in bundles and 
label with a piece of wood. Heal in the cuttings (and 
scions) by digging a trench in moist, sandy, well drained 
soil in a shady place as on the north side of a building. 
Place the bundles in the trench in a slightly inclined posi- 
tion and cover all over but the tips, pressing the soil 
firmly about them. 

In February or March, when the nursery is ready, 
dig up the cuttings and plant in nursery rows, making the 
rows 2 feet apart for hand cultivation or 3 feet apart for 
horse cultivation and plant the cuttings 8 inches apart in 
the rows. 

Only berries, fig, olive and quince are raised by cut- 
tings, but for the sake of experiment and practice try cut- 
tings of the others. 



62 MANUAL OF GENERAL AGEICULTUET!. 

57. ESTABLISHING A DECIDUOUS ORCHARD. 

The operations involved in the establishment of a de- 
ciduous orchard are as follows : 

1. Collection of Seed. When seeds are to be col- 
lected on a large scale it is usual to get them from some 
cannery, but when only a few are desired they may be 
obtained in any convenient manner. As seeds planted 
seldom come true to types, all plantings of seed must be 
made with the knowledge of the kind of scions that are 
to be grafted or buds to be budded on the young seed- 
lings. For instance, it is customary to make combinations 
about as follows : Peach budded on peach, preferably on 
strong growing yellow peach seedling. Pear, budded or 
grafted on pear, preferably on Keiffer pear. Apple 
grafted on apple. By root grafting onto roots of the 
Northern Spy apple, trees obtained are said to be immune 
from attacks of the "Woolly Aphis. Plum or prune budded 
on peach in moist, sandy loam soils. Plum budded on 
Myrobolan when subject to overflow, standing water, or 
on heavy soil. Apricot, same as plum. Walnut grafted 
on California black walnut. Quince, olive and fig are 
grown from cuttings. 

After the seeds are collected keep them in a cool dry 
place, but not in an air-tight receptacle. Obtain at least 
five seeds of each fruit to be propagated and ten of the 
smaller kinds as they are more likely to be lost. 

2. Stratification of Seed. In January obtain some 
cheesecloth and cut into squares of about a foot each, 
making twice as many squares as you have sets of seeds. 
Moisten all the cloths with water. Take the seeds pre- 
viously collected and select a spot in the garden, prefer- 
ably one in sandy soil. Dig a hole a foot square and a foot 
deep. In the bottom spread out one of the cloths and place 
on it any set of seeds ; then over them place another cloth 
and two inches of soil. Place another cloth, seeds, cloth, 
and soil, in the same way until all the seeds have been 
stratified. Record in your note book the various strata. 
Of course if there are more than five sets of seeds to be 
stratified the hole must be deeper than a foot or prefera- 



aCANUAL OF GENEEAL AGEICULTUEE. 63 

bly, dig two holes rather than go beyond a foot deep. 
Place a stake by the seeds with your name on it so that 
they may be readily located. Allow the seeds to remain in 
the ground about six weeks. 

3. Transplanting to the Nursery. The best location 
for a nursery is on loam or sandy soil, but trees may be 
successfully grown in less favorable soil. The land should 
be plowed deep and thoroughly cultivated. By the use of 
string and stakes dig with a hoe a trench the desired 
length. No definite depth can be given for planting the 
seeds, but the smaller ones such as pear or apple should 
be planted one and one-half inches deep, while the larger 
ones like the peach or apricot two inches deep. 

Carefully dig up the stratified seeds and take them 
to the nursery taking care not to injure the young sprouts. 
Plant them in rows about six to eight inches apart. The 
rows should be about three and one-half feet apart for 
horse cultivation, but for hand cultivation two feet is suf- 
ficient. Plant only the sprouted seeds. Mark with stakes 
the location of each set of seeds. The stakes should be 
uniform in size and, if desired, painted white. A con- 
venient size for stakes is 1x2x24 inches. 

4. Stripping the Young Seedlings. By the following 
summer it will be found that the small branches have 
grown down close to the ground. In order to facilitate 
the operation of either budding or grafting it is necessary 
to break off with the fingers the young limbs close to the 
ground and up to a distance of five or six inches, accord- 
ing to the size of the tree. Nothing else need be done to 
the trees the first summer, but of course the ground should 
be well cultivated, weeds kept down and irrigation prac- 
ticed according to local conditions. 

5. Grafting and Budding. Grafting. Where graft- 
ing is to be done the scions of the desired varieties should 
be secured when the trees are pruned in December or 
January. Care for the scions and insert them as described 
in Exercise 56. Budding. What is commonly called 
"June Budding" is usually practiced in California in 
April or May. The bud is inserted close to the ground in 



64 



MANUAL OF GENEEAL AGEICULTURE. 



either of these months. In selecting the bud go to some 
tree that produces the desired variety of fruit and cut off 
a few vigorous growing limbs. Carry limlis and all to the 
nursery and then cut and insert buds as described in Ex- 
ercise 59. 

6. Heading Back to the Bud. After the bud has 
grown into a branch from four to six inches long, head 
back to the bud by cutting with a sharp knife the main 
stock completely off just above the bud. (Fig. lie). 

7. Dig-ging the Nursery Trees. The following Feb- 
ruary the trees will be about two years old from the seed, 
but the age of a tree is not reckoned from the time of 

planting the seed, but from the time of 
inserting the bud or graft. Our trees are 
therefore considered as one year old. 
(Large nurserymen often obtain one year 
old seedlings from France at a low cost, 
thus saving a year's time.) 

In February dig the trees from the nur- 
sery rows so as to obtain a large number 
of small branching roots. (Previous to 
digging, the orchard should be made 
ready to receive the young trees as de- 
scribed in Exercise 60.) In lifting 
from the nursery, digging with a well- 
sharpened spade, which will sever the 
long roots cleanly, is perhaps the best 
method. The tap root cuts no figure in 
California orchard planting, but it is im- 
portant to have as many small lateral 
roots as possible. Any broken roots 
should be clipped off. Do not permit the 
roots after lifting, to dry out. Cover them with wet sacks 
or wet straw unless they are to be planted immediately. 
If trees after digging are not to be planted the same 
day they may be kept by being "healed in." To heal in, 
dig a trench in light, moist, but well drained soil ; put the 
trees in singly, side by side, laying the tops all one way, 
then shovel the earth over the roots until they are well 




MANUAL OF GENEEAL AGEICULTURE. G5 

covered with loose soil. Be sure the soil sifts down well 
between the roots. 

This is the way to care for trees received from any 
nursery if they are not to be planted at once. In remov- 
ing from the trenches be sure the roots do not dry out. 
Directions for planting are given in Exercise 61. The 
trees should be cut back to 18 inches just before planting 
as shown in figure 3. 

58. GRAFTING. 

Materials: Grafting knife or medium large pocket 
knife with sharp blade, saw, thin chisel or grafting tool 
(Fig. 5) or screw driver, 2 quart pail, round paint brush 
about three-fourths inches in diameter, grafting wax pre- 
pared as follows: In the pail place one pound of resin, 
one pound of beeswax and one-half pound of rendered 
tallow (obtained by melting beef tallow and allowing it 
to cool.) Thoroughly melt, stirring occasionally with the 
brush. Waxed string. Before removing the melted graft- 
ing wax from the fire place into it a ball of No. 18 knit- 
ting cotton. Leave it in the wax for several minutes, 
turning frequently. Remove from the pail and allow to 
drain and dry. 

Were all forms of the art of grafting to be taken from 
the horticulturist today, commercial fruit growing in its 
high state of perfection would decay with the orchards 
now standing. All the common pomaceous fruits (apples 
and pears), the stone fruits (peaches, plums, cherries and 
apricots), and citrus fruits (lemons and oranges), are now 
multiplied by grafting and budding. The progress in 
plant breeding and the great rapidity which new sorts 
are now distributed could not be obtained without the aid 
of budding or grafting. Under the existing conditions it 
is not necessary for the originator of a new sort of apple 
to give any thought to the question of fixing that type so 
it may be reproduced by seed. Grafting and budding has 
settled that long ago. 

(a) Whip Grafting. This style of grafting is the 
one most universally used. It has the advantage of being 



66 



MANUAL OF GENERAL AGRICULTURE!. 



well adapted to small plants only one or two years old. 
Also it may be used on seedlings standing in the nursery 
or on seedlings or roots dug up and the work done on a 
bench. 

1. Grafting Seedlings in the Nursery. The stock is 
the plant or part of it upon which the bud or scion is in- 
serted, in this case the seedling trees. ]\Iake the graft by 
cutting the stock off di- 
agonally just above the 
ground. Make one long 
smooth cut with a sharp 
knife, leaving about 
three-fourths of an inch 
of cut surface as shown 
in figure 4, a. Place 
the knife about one- 
third of the distance 
from the end of the cut 
surface, at right angles 
to the cut, and split the 
stock in the direction of 
its long axis. Cut the 
scion with about three 
buds, then cut the lower 
end as shown in figure 
4, b, so that when the 
stock and scion are 
forced together as 
shown in figure 4, c, the cut surface will fit neatly together 
and one will nearly cover the other if the stock and scion 
are of the same size. The importance of having an inti- 
mate connection between the growing tissues (the cam- 
bium layers) of both stock and scion, cannot be too 
strongly emphasized, for upon this the success of grafting 
depends. A difference in diameter of the two parts to be 
united may be adjusted by placing the scion so that the 
cambium layers meet on one side only, but it is desirable 
to have stock and scion nearly the same size if possible. 




Fig. 4. — Whip grafting; a, the stock; 
h, the scion; c, stock and scion united. 



MA.NUAL OF GENERAL AGRICULTURE. 



67 



After the parts have been forced together, tie them with 
waxed string, then coat with grafting wax. 

2. Grafting Seedlings not in the Nursery. Root 
Grafting. This is the prevailing Eastern method and is 
not so much in use in California except for root grafts on 
Northern Spy apple stock. Cut the scion with about three 
buds as before and cut the stock about as long as the scion. 
Tf the roots are to be used cut them into lengths of about 
five or six inches. 

The stock and scions are obtained in the fall or in 
December and stored until February or March, when 
grafting can be done. They may be packed away in moss, 
sawdust, or in sand or healed in, in the usual way. (See 
Ex. 56.) In the spring when setting out in the nursery, set 
the root graft just below the surface of the ground and 
the seedling graft just above the surface. 

Cleft Grafting. This style of graft is particularly 
adapted to large trees when for any reason it becomes 
necessary to change the variety. Branches too large to 
be worked by other methods can be cleft grafted. Saw off 
a branch to be grafted, being careful not to loosen the bark 
from the portion of the 
stub. Split the exposed 
end with a broad, thin 
chisel or grafting tool 
or hatchet, (tig. 5). 
Then with the wedge- 
shaped prong at the end 
of the grafting tool or 
with a hatchet or even 
a screw driver, spread 
the cleft so that the 
scions (fig. 6, a) may be 
inserted (fig. 6, b.) The 

scion should be of the ■ei,^ - ^ v.._ +„„, 

, Fig. o. — Grafting tool. 

previous seasons 

growth and should be long enough to have two or three 




68 



MANUAL OF GENERAL AGRICULTURE. 



buds. Cut the lower end, which is to be inserted into the 
cleft, into the shape of a wedge, having the outer edge 
thicker than the inner 
(fig. 7.) Cut a scion so 
that the lowest bud will 
come just at the top of 
this wedge, so that it 
will be near the top of 
the stock. The advan- 
tage of cutting the 
wedge thicker on one 
side is illustrated in 
figure 7, which shows 
how the pressure of the 
stock is brought upon 
the outer growing parts 
of both the scion and 
the stock, whereas were 
the scion thicker on the 
inner side the condi- 
tions would be reversed, 
and the death of the 
scion would follow. To 
make the contact of the 
growing portion doubly certain, set the scion at a slight 
angle with the stock into which it is inserted in order to 
cause the growing portions of the two to cross. After the 
scions have been set, complete the op- 
eration of cleft grafting by covering all 
cut surfaces with a layer of grafting 
wax. In case both scions "take," after 
a good growth of leaves has appeared, 
cut off evenly at the stock the scion 
which appears the weaker. Wax the 
cut place. Only one should be allowed 
to continue growing. 




^M 



Fig. 6. — Cleft grafting; a, the scion; 
b, scions inserted in cleft. 




Fig. 7. — Cross sec- 
tion of stock and 
scion. 



MANUAL OF GENERAL AGRICULTURE. 



69 



59. BUDDING. 

Material: Budding knife, but a medium or a large 
sized pocket knife will do if sharp, and raffia. 

There are numerous styles of budding, but 
only the one in most common use will be de- 
scribed. Budding is one of the most econom- 
ical forms of artificial reproduction and 
each year witnesses its more general use. It 
is economical in the amount of wood used 
from which to take buds. In this method a 
single bud does the work of three or more 
upon the scion used in grafting. The opera- 
tion of budding is simple and can be done 
with great speed by expert budders. Bud- 
ding may be done from May to September. 
The usual plan is for a man to set the bud 
and a boy follow closely and do the tying. 

(a) The Bud. — Obtain buds from wood 
of the present season's growth. The work 
of budding is done during the season of ac- 
tive growth. Prepare the bud stick so that 
the petiole or stem of each leaf is left at- 
tached to serve as a handle to aid in pushing 
the bud home when inserting it beneath the 
bark of the stock. This is what is usually 
called a shield bud and should be cut so that 
a small portion of the woody tissue of the 
branch is removed with the bud. A bud stick 
is shown in figure 8. The operation of cut- 
ting the bud is illustrated in figure 9. The 
stock for budding should be at least as thick 
as an ordinary lead pencil. 

(b) The Operation. — The height at which 
buds are inserted varies with the operator. 
In general the nearer the ground the better. 
Make the cut for the insertion of the bud in 
the shape of the letter T (fig. 10, a). Usually 
the cross cut is made not quite at right 
angles with the body of the tree, and the 




Fig. 8. — a 
bud stick. 



70 



MANUAL OF GENERAL AGEICULTURI!. 




Fig. 9. — Cutting the bud. 



Fig. 10. — Budding — preparing the 
stoclc. 

stem to the T starts at the crosscut and extends towards 
the root for an inch or more. The flaps of bark caused by 
the insertion of the two cuts (fig. 10, b) should be slightly 



MANUAL OF GENEEAL AGEICULTUEE. 



71 



loosened with the ivory heel of the budding knife, and the 
bud, grasped by the leaf stem as a handle, placed under 
the flap and firmly pushed into place until its cut surface is 
entirely in contact with the peeled body of the stock (fig. 
11, a). Raffia is then tightly drawn about, above and be- 
low the bud to hold it in place until the union shall be 
formed (fig. 11, b). Bands of raffia about 16 or 18 inches 
long make a most convenient tying material. As soon as 
the buds have united with the stock, the raffia should be 
cut in order to prevent girdling the stock. This done, the 
operation is complete until the following spring, when all 
the trees in which the buds have "taken" should have 
the tops cut off just above the bud (fig. 11, c). The re- 
moval of the top forces the entire strength of the root 
into the bud, and since the root itself has not been dis- 
turbed by transplanting, a more vigorous growth usually 
results from the bud than from scions in whip grafting 
when the roots are disturbed. 






Fig. 11. — Budding; a, inserting the hud; b, tying ; c, cutting off 
the top. 



72 MANUAL OF GENEEAL AGRICULTUE]';. 

60. LAYING OUT AN ORCHARD. 

In laying out an orchard it is necessary to have one 
side and one end of the field at right angles. Often there 
are regular subdivisions to work from ; but, if there are 
none, these two lines, called base-lines, may be estab- 
lished with a transit. If the base-lines cannot be estab- 
lished in any other way, proceed as follows to find a 
square corner. Begin at the corner stake and measure 
off 60 feet along one line with a steel tape, and put in a 
stake. Then from the starting point measure off 80 feet 
as nearly at right angles with the first line as can be 
judged with the eye, and describe an arc of several feet, 
holding one end on the corner stake. Then from the 60 
foot mark measure diagonally across to a point on the arc 
that is 100 feet from the 60 foot mark and set a stake 
there. The three stakes will then form a square corner. 
The distances 30, 40 and 50 feet would do as well, if your 
tape is only 50 feet long. 

There are two methods of planting, the square and 
the equilateral triangle, but as the square method is the 
one in general use, this method alone will be described. 

Make at least thirty stakes about half an inch square 
and one foot long. These may be split out of redwood or 
pine. (If six inches of the end of each is dipped in white- 
wash they can be readily seen, and should any of the 
stakes be out of line it will be noticed at once.) 

Obtain a piece of No. 10 gauge galvanized wire ; and, 
if the trees are to be 20 feet apart, the wire should be 202 
feet long; if 24 feet apart 242 feet long, etc. Attach to 
each end of the wire a three-inch iron ring by bending the 
wire. Not over a foot from the original end of either end 
of the wire, wrap a piece of small wire, making three laps 
and solder into place. 

In the same way solder into place a small piece of 
wire every 20 feet along the wire if the trees are to be 
20 feet apart. In handling the large wire be careful not 
to get a kink in it as it can be easily broken in this way. 

Having established base-lines, place a stake in each 
corner of the field, set stakes for ten trees for each stretch 



MANUAL OF GENEEAL AGRICULTURE. 73 

of the wire by stretching the Avire along one of the base- 
lines. Having set the stakes along the outside line, start 
at the same end of the field again, and set another line of 
stakes, parallel with the first and the length of the wire 
(chain) from it. Follow out this method until the entire 
field is laid out in checks. With the check lines estab- 
lished it is only necessary now to set stakes at the 20 foot 
marks on the wire where the trees are to be planted. 

61. HOW TO PLANT A TREE. 

Materials as descri))ed in experiment. IMake a tree- 
setting board out of a piece of pine one inch by 4 inches 
by four feet long. About an inch from each end of the 
board, bore a hole an inch or so in diameter. Then saw 
a triangular notch in the middle of one side of the board, 
making the notch about one inch across and one and 
one-half inch deep. 

Make two stakes small enough to be driven through 
the holes, and a foot in length. Place the notch against 
the stake where the tree is to be planted and push the 
stakes through the holes into the ground then remove 
the center stake and board. Dig a hole not less than 
eighteen inches in diameter and eighteen inches deep. 
After the hole is dug, replace the board over the end of 
the stakes and plant the tree with the trunk resting 
against the center notch. In setting out the tree, one 
person should hold the tree in an upright position against 
the notch while another shovels or fills in loose soil around 
it, first spreading out the roots and rootlets in as natural 
position as possible. The surface soil should be put in 
first among the roots taking care to fill every interstice, 
thus bringing all the roots in direct contact with the soil. 
When the hole is two-thirds full, firm the earth thoroughly 
about the roots, but before doing this draw the tree up 
to its permanent position. The top three or four inches 
should not be tramped unless the ground is wet from 
recent rains. Scoop a basin out around the tree which 
will hold at least ten gallons of water and apply water 
either by bucket or irrigation. The following day draw 



74 MANUAL OF GENEEAL AGEICULTURIl. 

in loose soil and fill up the basin. From a soil mulch 
by reducing this top soil to as fine a condition of tilth as 
possible. Guard against setting too deeply, but allow for 
the settling of soil so that when once established the tree 
will stand about as it did at the time of removal from 
the nursery. 

62. PROPAGATION OF THE GRAPE. 

The prevailing method of propagating the grape is 
by growing from cuttings. 

There are two distinct types of vineyards. We may 
establish a vineyard on its own roots ; or establish a 
vineyard on resistant roots. 

(a) VINEYARD ON ITS OWN ROOTS. 

1. Securing the Cuttings. A good cutting consists 
exclusively of one-year old wood ; that is, wood which 
has grown the previous season. The cuttings can be se- 
cured during the winter pruning (January), when the 
vines are dormant. In a moist soil in a cool region they 
should be about sixteen inches long but in drier regions 
about twenty inches long. It is not possible to make all 
cuttings exactly the same length because they should 
terminate at each end at a node. Cuttings should be 
from three-eighths to five-eighths of an inch in diameter. 
Take great care not to injure the bud at either terminal. 
Cut off all intermediate buds. Cuttings from the outer 
ends of long canes are not so likely to root. 

2. Care of Cuttings. Cuttings should be kept dor- 
mant until the time comes for setting them out. This 
may be done by tying them in bundles of convenient 
size, in this case put fifty in a bundle. After labeling 
by means of a stick of wood tied to the bundle, dig a 
trench as deep as the length of the bundles on the north 
side of a tight board fence or shed, making the trench 
wide enough to receive them. Place them in it in a 
nearly upright position and cover with loose earth and 
on top put some straw. They should be in moist but not 
wet ground as too much moisture rots them. 



MA.NUAL OF GENERAL AGRICULTURE. 75 

3. Planting the Cuttings. The cuttings can either be 
planted in the field or in the nursery. If they are to be 
planted directly in the field, planting may be done the fol- 
lowing March as described below. Owing to the fact that 
only from 50 to 80 per cent of the cuttings will take root, 
or form vigorous roots, it is lisual and far more desirable 
to transfer the cuttings to the nursery in March, allowing 
them to take root and remain there one year. (This is 
the method we shall pursue.) At the end of that time 
only vigorous rooted cuttings need be used and thus a 
much more perfect stand in the vineyard can be obtained. 
In planting in the nursery rows, make the rows four feet 
apart for horse cultivation and two feet apart for hand 
cultivation, in either case planting them three to four 
inches apart in the rows. The nursery should be in loose, 
moist soil so that a good root system will develope. Leave 
the upper bud just above the surface of the ground. 

4. Transferring to Vineyard. A year later when 
planting in the vineyard it is customary in heavy soils to 
plant 8 by 8 feet apart, but in light soils 12 by 12 feet 
apart, laying out the vineyard the same as an orchard. 
Dig the holes the width of a spade and the length of the 
cutting in depth. Leave the top soil to one side so that it 
can be put into the hole first wiien filling. 

When all or a part of the holes are dug, dig up the 
cuttings and if not very moist place them in water for at 
least 24 hours ; otherwise transfer directly to the vineyard 
after digging and plant as soon as possible — in any case 
the same day, but before planting trim the roots back to 
from 2 to 3 inches. In planting place a cutting in a hole 
and shovel in the top soil first so that when the cutting is 
leaning against the side of the hole there will be one bud 
just above the surface of the ground when the filling is 
complete. Continue filling the hole until it is about half 
full, then tramp down with the foot. Continue filling the 
hole so that when the hole is completely filled the bottom 
soil is on top. Again tramp down the soil about the cut- 
ting and finally leave a soil mulch over the entire area 
covered. 



76 MANUAL OF GENEEAL AGRICULTUEE. 

b. VINEYARD ON RESISTANT ROOTS. 

American wild vines are characterized by marked 
differences in degree of resistance to Phylloxera, a very 
destructive insect. By selection a few wild types have 
been secured that are almost immune to the attacks of this 
insect. For a deep soil Rupestris St. George is used as the 
stock ; for dry soils or on hill sides Reparia x Rupestris 
3309. The disease does not spread much in sandy soil so 
that it is advisable to establish the vineyard on its own 
roots in this case. 

A resistant vineyard may be established in either of 
two ways: 1. By Field grafting; or 2. By Bench graft- 
ing. 

1. Field Grafting. This may be accomplished by 
planting resistant cuttings directly in the vineyard and 
field grafting, or grafting in the field the following win- 
ter. Only a 50 to 80 per cent stand can be obtained by this 
method, hence it is not in favor. 

2. Bench Grafting. Secure cuttings from resistant 
vines such as Rupestris St. George or Reparia x Rupestris 
3309 during the dormant period, or at the time of prun- 
ing (January.) If necessary secure these cuttings from a 
nurseryman. Likewise secure scions from the desired 
varieties to be propagated. The scions may be any con- 
venient length — two or three feet. Select both cuttings 
for stock and cuttings for scions from strong growing 
healthy vines. They should be of the same size to be ac- 
curately matched in grafting. Heel them in until some 
convenient time in late winter or early spring (March), 
then dig them up and graft. (The work is usually done 
on a bench, hence the name "bench grafting.") The 
scions should have one bud and should be long enough to 
handle while grafting — two or three inches. Do not tie 
with raffia or use grafting wax. Keep the grafted stock in 
bundles of convenient size in moist sand in a warm place, 
or preferably in a warm room when a callus will form at 
each joint. A month later they may be planted in the 
nursery. The following spring transfer to the vineyard. 
In planting any kind of rooted vines prune the roots to 



MANUAL OF GENERAL AGEICULTURE. 77 

two or three inches in length at the time of planting. This 
method of establishing a vineyard is the accepted French 
one and has proved successful in California. 

63. PROPAGATION OF THE ORANGE. 

(The following applies to the lemon and pomelo as 
well as to the orange.) 

The propagation of the orange differs considerably 
from the propagation of deciduous trees. 

1. Selecting and Planting- the Seed. Select seeds 
from the sweet orange, Florida sour orange or pomelo 
with which to grow the stock. Plant the seeds in a seed 
bed sheltered by a lath house or in the open, but in either 
case the seed bed should be well drained, mixed with a 
light soil and mulch and finally covered with a layer of 
light sand. In preparing in spring plant the seeds an inch 
deep and IV2 inches apart. 

2. Digging the Seedlings. One year later remove the 
seedlings to the nursery, planting them in rows. The rows 
should be about 39 inches apart for horse cultivation, but 
for hand cultivation 16 inches is sufficient. In either case 
plant the trees about one foot apart in the rows. 

3. Budding the Seedlings. The seedlings should be 
budded after being in the nursery either one or two years. 
A week or two before the operation, strip the seedlings by 
removing all leaves and thorns from the lower six inches 
of the trunk to make room for the bud. Insert the bud 
two or three inches above the ground. The best time to 
bud is in the spring. Budding may also be done in mid- 
summer or in the fall. The growth from the summer buds 
is likely to be killed by frost during the first winter. Fall 
buds lie dormant during winter and start the following 
spring. When the bud attains 6 to 8 inches growth, re- 
move the top of the tree as shown in figure 11, c. 

4. Transferring to Orchard. After one or two years 
the trees should be transferred to the orchard. The most 
common method is to "ball them," that is, to remove a 
ball of earth with the roots, tying a sack around them to 
keep the soil from falling away. 



78 MANUAL OF GENEEAL AGEICULTUEK 

The usual method of planting is in squares. The trees 
should not be less than 20 feet by 20 feet apart. 

64. PRUNING FRUIT TREES, VINES AND BUSHES. 

To know how to prune the various fruits, we must 
know upon what kind of branches each bears its fruit and 
the age of the branches. 

The Age of Branches. Take a pear branch and, be- 
ginning at the tip, follow it back until you find a point 
where there is a slight bulge and many tiny scars. This 
marks the end of one year's growth and the beginning of 
another. Follow on down the branch and determine its 
age. In most cases, the age of a branch of a fruit tree can 
be determined in this way. With many of the vines and 
bushes these rings are lacking, or are not so noticeable, 
and the color and condition of the bark is a better guide. 

The Pear — fruit bearing habit. The short branches 
bearing the fruit are called fruit spurs. What are the 
ages of the various parts of the main branch which bear 
the spurs? The spurs are each one year younger than the 
branch upon which they are borne. Why? If an un- 
branehed spur produqes a fruit this year, it also produces 
a vegetative bud at the base of the fruit, which next year 
continues the growth of the spur and produces a fruit bud 
in the fall. This causes the zigzag growth characteristic 
of pear and apple spurs. 

Draw a pear spur and a portion of the main branch, 
showing : 

1. Annual ring of growth. 

2. Fruit scars. 

3. Fruit. 

4. Vegetative bud. 

How old is this spur? What is the oldest wood on the 
branch having fruit bearing spurs? The youngest? 

Pruning. It usually requires two or more years for 
a young branch to produce fruit ; such a branch may bear 
fruit for many years. As a branch grows out year after 
year, the fruit bearing area moves out also, the older parts 



MANUAL OF GENEEAL AGEICULTUEE. 79 

ceasing to produce. If we head back a branch, the fruit- 
ing area cannot be renewed until new branches are formed. 

A fruit spur may change its function and become a 
branch, which in time may produce new fruit spurs. If 
we prune away too much foliage bearing wood, the tree 
restores the balance by changing spurs to branches. Ex- 
amine branches and find examples of this. 

If we cannot head in and must avoid excessive prun- 
ing, how, then, should we prune the pear? 

The Apple. The fruit bearing habit of the pear and 
apple is practically the same. Examine an apple branch 
and prove this. 

The Peach — fruit bearing habit. In this case the fruit 
is not borne on spurs, but directly on one-year-old 
branches. Occasionally these branches are so short as to 
look like spurs. On a branch which has grown this sea- 
son, find a single node which has produced three leaves ; 
carefully remove the leaves and study the buds in their 
axes. Next spring the two outer ones will try to produce 
flowers and the middle one leaves. 

Notice the following: (1) Wood older than one year 
bears no fruit. (2) The fruit is borne on the middle and 
lower portions of one-year wood. (3) Only vigorous one- 
year wood produces fruit in quantities. (4) The upper 
buds tend to produce branches. (5) Compare the buds 
on this season's wood with what came from the buds on 
last season's wood. Draw a branch which has grown this 
season (first removing the leaves) and indicate the nodes 
at which fruit buds are being formed. 

Pruning'. To produce fruit, we must have a vigorous 
growth of new branches each year. How may we prune 
the peach to secure this? 

The Cherry — fruit bearing habit. In the cherry we 
have fruit borne similar to the pear, and also similar to 
the peach, that is, we find some fruit on one-year wood 
and some on fruit spurs. Near the base of this season's 
wood you will find single buds that are more plump than 
those further up the branch ; these will bear fruit next 
year. There is no foliage or vegetative bud at this point, 



80 MANUAL OF TTENERAL AGEICULTURIl. 

SO that the lower portion of the branch remains bare after 
the fniit is picked. The side branches are all grouped on 
the upper part of the year's growth. The age of a cherrj'- 
tree can frequently be told by counting these groups of 
side branches. 

Pick off a spur and notice that its growth has been 
straight, and not zigzag, as in the pear. The central bud 
of the cluster is a foliage bud and continues growth year 
after year. It is more pointed than the surrounding fruit 
buds. What is the age of the oldest branch that you can 
find bearing fruit spurs? 

Pruning. Only a very small amount of the fruit is 
borne on one-year wood. It is the fruit spurs which are 
important. With this point in mind, how would you 
prune the cherry? 

Picking Fruits which Possess Fruit Spurs. If a spur 
is broken off, there are no buds left to renew it. In pick- 
ing, the fruit should be separated from the spur. Many 
cherry trees become unproductive because the pickers 
have broken off the clusters of cherries and thus removed 
the spurs. 

The Grape — fruit bearing habit. The grape is differ- 
ent from both the pear and the peach. In the winter you 
can find no fruit buds ; all buds then are vegetative. In 
the spring from each bud comes a cane which produces 
flowers and fruit that same season. Examine a grape cane 
and verify this. Notice that the fruit is produced usually 
at the second, third and fourth nodes only, that is, each 
bud found on the vine in winter tries to produce a cane 
which will bear from two to three fruit clusters; therefore 
by limiting the number of buds which we leave on the 
vines, we limit the number of fruit clusters which the vine 
will produce. The maximum number of good clusters that 
a vine will produce ranges from twenty-five to fifty. 

Pruning. The grape must be cut back every year so 
as to have from fifteen to twenty buds only. 

Blackberries and Raspberries — fruit bearing habit. 
These produce fruit on the branches grown this season in 
the same way as the grape. The first year a straight cane 



MA.NUAL OF GENERAL AGRICULTURE. 81 

is sent up, the second year this forms side branches, which 
terminate in fruit clusters. After the fruit matures the 
cane dies. 

Pruning. How would you prune the raspberry? 

(Let the teacher arrange field exercises in winter and 
prune as many different kinds of fruits as are available.) 

65. STRUCTURE AND NATURE OF FUNGI. 

Materials: Mouldy bread, (see exercise) dish, lens 
and compound miscroscope. 

The piece of bread furnished has been moistened, a 
bit of mouldy stable manure placed upon it, then placed 
in the dish and kept covered for a week. 

1. Mycelium of the Fungus (pi. fungi.) Examine 
with a lens, notice the white, mouldy growth — the myce- 
lium of the fungus. It corresponds to the roots, stems and 
leaves of other plants. It takes its food from the bread. 

2. Sporangium. Notice that the dark color is due 
to black specks attached to the mycelium threads by 
means of a stalk. These are spore cases. Each one is 
called a sporangium. Some are white. They are the 
young unripe ones. The spores correspond to seed and 
the sporangium corresponds to a pod. Mount some of the 
fungus in a drop of water and examine with the low 
power of a compound microscope. Make drawings of the 
mycelium, sporangium and spores. 

66. STRUCTURE AND NATURE OF BACTERIA. 

Materials: Potato, needle, compound miscroscope. 
(Let the teacher send to the State Hygenic Laboratory, 
Berkeley, Cal., and ask for the loan of a box of bacterio- 
logical specimens prepared especially for schools. There 
will be no expense except for express both ways.) 

Bacteria are the smallest of all known plants. They 
are to be found almost everywhere, on the earth, inside 
and outside the bodies of living animals and plants, in 
water, in milk, and on the dust particles of the air. Wher- 
ever moisture and food are present, some species will grow 
and multiply hindered only by extremes of temperature, 



82 MANUAL OF GENERAL AGRICULTURE. 

light, oxygen, or toxic substances. A few are known to 
cause diseases of man and animals, a rather large number 
(about 125) are now known to cause diseases in plants. 

Some Common Bacteria. Their Structure and Nature. 
In the material provided, the bacteria are growing on 
slices of cooked potato exposed to the air of laboratory for 
three minutes, covered, and then set in a warm place for 
several days. What conditions favorable to plant growth 
were provided? Observe: 

1. The more or less circular patches of various sizes 
and colors on the surface of potato — the colonies of bac- 
teria. How can you tell them from molds? Note the dif- 
ference in form and character of margins of different col- 
onies. Each colony was formed by the multiplication of 
a single bacterium. 

2. Compare different colonies as to nature of the 
surface, moist, dry, shiny, dull, smooth, wrinkled, etc. 

3. Note that some colonies are covered with a skin 
or pellicle, made up of bacteria stuck together by their 
gelatinous wall and dried by exposure to air. With needle 
determine toughness of pellicle. 

4. Bacteria feed on substances dissolved from the 
potato. Some colonies penetrate the potato, others sim- 
ply pile up. 

5. Bacteria, in their growth, produce gases with 
offensive odors, such as the odor from the potato. The 
common odors of decay are of this nature. Map the sur- 
face of the potato. 

6. With the point of the needle touch the different 
colonies, drawing the needle slowly away. Note that 
some are viscid, drawing out into long threads as the 
needle is removed. Clean your needle. 

Selecting a colony with wrinkled surface, remove 
from the smooth, glistening margin a bit on the point of 
your needle. Stir it into a drop of water on a clean slide. 
How does it affect the water? Why? 

7. Under low power, note the finely granular appear- 



lilANUAL OF GENERAL AGRICULTURE. 83 

ance of the water. Can you make out the individual 
plants? This power of your microscope magnifies 50 
times. Selecting a thin place in the mount turn on the 
high power and observe : 

8. The very small, short rod-shaped bacteria ( magni- 
fied about 500 times.) 

9. In many cases longer rods made up of 2 or more 
plants fastened. Each plant is a single bacterium. They 
multiply by the simple division of each plant into two. 
They may reach their full growth in less than half an 
hour. Draw. 

Make mounts on clean slides from differently appear- 
ing colonies. Compare the bacteria from these different 
colonies as to form, size, etc. Do they seem to be all alike? 
Are all the bacteria in any given colony alike? (Do not 
use the same slide more than once without thorough wash- 
ing and clean your needle each time before making a 
transfer). Are the bacteria from different appearing colo- 
nies always different in form, size, motility, etc.? 

PART V— ENEMIES OF CROPS. 
67. APPLE SCAB. 

Of all diseases of the apple, this is the commonest and 
best known to the growers. It is the one fungus disease 
for which they spray. It is world wide, occurring prac- 
tically wherever the apple is grown. While there is a 
marked difference in the susceptibility of varieties, all will 
suffer some under conditions especially favorable to the 
fungus causing the disease. The scab of the pear is very 
similar in its symptoms to that of the apple, but is 
caused by a distinctly different species of fungus, which, 
however, is closely related to the apple scab fungus. In 
either case the remedy is the same. 

THE DISEASE. 

SYMPTOMS. The disease affects the leaves, flowers, 
fruit and rarely the twigs. It lives over winter on fallen 
leaves. 



84 MANUAL OF GENERAL AGRICULTUEE. 

On the Leaves. The first evidence of the disease in 
the spring is upon the unfolding leaves. The scab spots 
usually appear first upon the under surface. Later the 
upper surface becomes infected. Examine the leaves pro- 
vided and observe : 

1. The size, form and character of the spot. The 
radiating character of the markings of the lesion. To 
what due ? 

2. The character of the injury to the leaf. Does the 
injury shov5^ on the surface opposite the spot ? 

3. Difference in the character of the upper and un- 
der surface of the leaf itself. Of the scab spots on the 
two surfaces of the leaf. 

4. The variation in the character of the scab spots 
on different leaves. Make drawings to show the charac- 
ters of the scab spots on the upper and under surface of 
the leaves. 

On the Fruit. Where the infection of the calyx is not 
severe enough to prevent the fruit from setting, the apple 
as it enlarges shows the enlarging scab spots which be- 
come very evident as the season advances. In the young 
apples provided. Observe : 

5. The black scab spots. Their form, size and effect 
on the fruit. To what region on the apple are they largely 
confined? Why? 

6. The felty black center of the spot. In some cases 
this felt is gone at the center of the spot, which is hard, 
of a reddish brown color and often cracked. 

7. The papery rim of border of the spot. Best seen 
in the younger spots. This consists of the cuticle of the 
apple that had pried loose by the fungus as it spreads out 
from the center of the spot. Make drawings to show the 
points brought out in 5, 6 and 7. 

Sometimes these spots cause a dwarfing of the apple 
on the affected side so that they become one sided. 

The apple scab is caused by the fungus known as 
Venturia inequalis. It lives upon the surface of the host 



MANUAL OF GENERAL AGRICULTURE. 85 

or nearly so, prying off the cuticle and applying its my- 
celium closely to the host tissue. 

Control. One spraying just before and one immedi- 
ately after blossoming are most important for its control. 
If the scab is serious it may be necessary to spray a third 
time. The spray used is known as Bordeaux Mixture. It 
is made of copper sulfate and lime. Directions for its 
preparation are given in any of the references in Part V. 

68. FIRE BLIGHT. 

Materials : Read the experiment. Obtain Cornell Uni- 
versity College of Agriculture, Bulletin 272. In sections 5 
and 6 obtain specimens at blossoming time and press them. 
Later in 7 obtain fruit and preserve in a five per cent solu- 
tion of formalin, to which has been added enough copper 
sulfate to just color the water. The latter will hold the 
color in the fruit. Whenever possible fresh material 
should be used. 

This is the most common and best known bac- 
terial disease of plants occurring in this country. It 
affects apples, pears, quinces and occasionally plums, apri- 
cots, and a few ornamental and wild plants related to the 
apple family. The affected tissues are killed outright. 

Symptoms. The symptoms of this disease will be 
studied in the order in which they manifest themselves 
during the season on different parts of the tree, beginning 
with the first activity of the disease in the spring. 

The hold-over canker is the source for the first infec- 
tion in the blossoms in the spring. Typical cankers on the 
limbs of apple and pear trees have been provided. Study 
the specimens before you carefully and observe : 

1. The smooth, more or less sunken area in the bark, 
its margin sharply defined by a definite crack in the epi- 
dermis — the canker. In active cankers this margin is not 
sharply defined. Note the diseased spur or shoot at the 
center of each canker. 



86 MANUAL OF GENERAL AGEICULTURE. 

2. The margin. Note that it is irregular, the crack 
being formed by the drying away of the diseased tissue 
from the healthy when the active progress of the disease 
was suddenly checked. Dry or cold weather may thus 
check the spread of the canker. These specimens were 
taken in the autumn or winter. 

3. The surface of the canker. Note that it is smooth, 
seldom roughened or wrinkled. It is often checked in 
from the margin by drying. Compare Math the healthy 
bark in this respect. Locate the lenticles. 

4. Make a careful drawing of the canker you have 
studied. Label fully. 

These cankers are formed during the summer and 
early autumn, and in many of them the bacteria pass the 
winter dormant, or only slightly active in the partially 
living tissues along the margin. "With the increased tem- 
perature and rise of sap in the spring, these bacteria be- 
come active, spread rapidly into the adjoining healthy 
tissue, increasing the area of the canker and oozing out 
through the lenticles to the surface in sticky, milky drops. 
If active cankers are available make a careful drawing, 
showing large viscid, milky drops that have oozed out. 
(See Fig. 16 N. Y. Cornell Bulletin No. 272.) 

5. Blosson-> Blight. Bees and flies visit these active 
cankers in the spring to feed on exuding sap and then 
visit the opening blossoms, where they leave behind them 
some of the blight bacteria with which they are smeared. 
Here in the nectar and in the injuries made by the insects' 
claws in the tender tissue of the flower, the bacteria mul- 
tiply rapidly, killing the blossom. Study the specimen 
provided or Fig. 6, Cornell Bui. 272. Observe : 

6. The dead and blackened flowers. The leaves of 
the spur are also dead and brown. The bacteria have 
spread down the pedicles in the spur. The dead and 
blackened blossom spurs are usually the first striking evi- 
dence of the disease in the spring. The oozing cankers 



MANUAL OF GENERAL AGRICULTUEE. 87 

are usually overlooked. Make drawing of a blighted blos- 
som spur. 

7. Fruit Blight. Frequently only one blossom on a 
spur is infected and by the time the bacteria have killed 
it and worked their way down the pedicle to the spur 
itself, the uninfected blossoms have developed fruit of a 
considerable size. From the spur the bacteria now work 
into the base of these fruit pedicles and by way of 
them to the growing fruit. Study Fig. 6, Cornell Bui. 272. 
The curculio and aphids frequently introduce the bacteria 
into the fruit through their punctures. The disease does 
not always enter the fruit by the pedicle. Note that the 
leaves of the spur are also dead and shriveling. In rainy, 
muggy weather the bacteria ooze from these blighted 
fruits and blossoms in sticky drops as they do from the 
hold-over cankers. 

8. Twig Blight. The bacteria from the diseased 
blossoms and fruits are carried by sucking insects to the 
tips of the growing shoots and waterspouts and are there 
introduced through the wounds or punctures made by the 
insects into the tender, succulent tissues. Here they mul- 
tiply rapidly, killing the shoot, causing the form of the 
disease commonly known as "Twig Blight." Blighted 
twigs have been taken from the tree in summer and 
pressed. Examine the specimen provided and observe : 

9. The contrast between the diseased and healthy 
portions of the twig in both the twig and leaves. You may 
be able to find the dried ooze. Draw the blighted twig. 

10. In some of the specimens note that the dormant 
buds in the axils of the leaves just below the blighted por- 
tion have been prematurely forced. Explain this. 

The organism that causes this disease is Bacillus amy- 
lovorus. See Fig. 6, Cornell Bui. 272. 

11. Control of the Disease. No method of protecting 
the trees by means of sprays is effective because it is im- 
possible to reach the bacteria. The disease can be effect- 



88 MANUAL OF GENERAL AGEICULTUEE. 

ively controlled by inspecting the orchard at least once a 
week during the growing season, beginning as soon as the 
blossoms begin to fall, cutting out the diseased portions 
and disinfecting the cut surfaces with corrosive sublimate 
solution made by dissolving one tablet in a pint of water. 
(See Cornell Bui. 272.) If diseased trees are available see 
if you can control the disease in this way. 

Question : Point out the practical importance of each 
of the following facts about Fire Blight : 

1. It is a bacterial disease. 

2. It occurs only in North America. 

3. The bacteria causing the disease pass the winter 
in hold-over cankers in any of its numerous hosts. 

4. The bacteria get into the host only through 
wounds. 

5. The chief agents of dissemination are certain in- 
sects. 

6. The bacteria are usually introduced into the 
young and growing parts of the host, where in these suc- 
culent tissues they multiply and develop the disease very 
rapidly. 

69. THE MOUTH-PARTS OF INSECTS.* 
Materials: Lens, needle, forceps, grasshopper, honey 
bee, squash bug, moth. 

Insects that injure plants are of two classes. The 
distinction between these two classes is in the form of 
their mouth-parts. One class has its mouth-parts fitted 
for biting or chewing, while the other 
class has them fitted for sucking. Meth- 
ods of destroying insects are based on this 
difference in the structure of the mouth. 
Insecticides of one kind are used for kill- 
ing insects with a mouth fitted for biting. 
Such insects usually feed upon the leaves 
of plants. Poisons of different kinds are 
therefore sprayed or dusted upon the 

leaves. The poison is taken up by the in-^jg 12. The head 

sect with its food, producing in its ali- of a locust. 
*rrom Cornell Rural School Leaflet. 




MANUAL OF GENERAL AGRICULTURE. 89 

mentary canal changes that eventually cause its death. 
Insecticides of an entirely different kind are used for suck- 
ing insects. These insecticides usually contain a resin, 
alkali, oil, or a strong caustic, which corrodes or contracts 
and shrivels the body of the insect, covers the breathing 
pores located along each side of the insect's abdomen, and 
in this way causes its death. 

To determine what kind of insecticide shall be used 
to destroy any particular kind of insect, it is necessary to 
determine first what kind of mouth-parts it has. To be 
able to decide this question accurately, something must be 
known of the more essential structures of an insect's 
mouth. 

Mouth-parts Fitted for Biting. Observe that the head 
of an insect may be held either horizontally or vertically ; 
if horizontally, the mouth opening is at the extreme front 
end of the head ; if vertically, the mouth opening is at its 
lower end on a plane with the under side of the body. The 
locust or ordinary grasshopper, which has been selected 
as typical for those insects with biting mouth-parts, holds 
its head vertically with the mouth opening below, i' ig. 12. 
The locust is especially suitable for study, not only be- 
cause specimens can be obtained easily, but also because 
it is truly representative of the biting type of insect. 

The locust (grasshopper) mouth-parts consist of 
seven distinct portions: an upper lip (labrum), two biting 
jaws (mandibles), two holding jaws (maxillae — singular 
maxilla), the tongue (hypopharynx), and a lower lip (la- 
bium.) The labrum is a movable fiap closing the mouth 
opening in front. Fig. 13. The mandibles, Fig. 13 md, are 
strong, toothed jaws with sharp edges which move side- 
wise just behind the labrum and are used for cutting and 
grinding the food. The maxillae, Fig. 13 mx, are situated 
just behind the mandibles and like the mandibles move 
sidewise. Each maxilla bears on its outer end two finger- 



90 



MANUAL OF GENERAL AGEICULTURE. 



like appendages : one the galea, Fig. 13 gl, is more or less 
spoon-shaped, the other 
the lacinia, Fig. 13 Ic, 
pointed and with two 
teeth. The galea and 
lacinia aid in holding 
the food in the mouth, 
where it can be crushed 
by the mandibles and 
masticated. Each max- 
illa also bears on one 
side a five-segmented 
feeler or palpus (plural 
palpi), the maxillary 
palpus. The hypophar- 
ynx is a small tongue- 
like structure situated 
in the mouth and at- 
tached to the inner sur- 
face of the lower lip. 
Fig. 13 hy. The lower 
lip or labium. Fig. 13 lb, 
in the locust and other 
insects consists of a 
single piece ; it is in 
reality a pair of jaws 




Fig 
I, 



13. — The mouth-parts of a locust. 

lahrum; md, mandible; hy, hypo- 
pharynx; mx, maxilla; mp, maxillary 
palpus; gl, galea; Ic, lacinia; lb, la- 
bium,; Ip, labial palpi; pg, paraglos- 
sae; g, glossa. 



similar to the maxillae grown 
together on the middle line. The labium bears on each 
side a three-segmented feeler or palpus, the labial palpus, 
Fig. 13 Ip, and at its apex two large, more or less square 
flaps, the paraglossae. Fig. 13 pg, and at the bottom of the 
slit between the paraglossae, a minute projection, the 
glossa, Fig. 13 g. The glossa in the locust is rudimentary, 
but in many biting insects it is as long as the paraglossae, 
and, as will be seen later, forms an important part of the 
mouth of sucking insects. Detach and draw the parts 
shown in Fig. 13. 

The mouth-parts of the locust illustrate well the form 
and arrangement of the parts in the mouth of biting in- 



MANUAL OF GENERAL AGRICULTURE. 91 

sects in general. The biting type is found in cockroaches, 
locusts, crickets, beetles, caterpillars, and larvae of prac- 
tically all kinds. Certain beetles, like the plum-curculio, 
have the front of the head produced into a long snout or 
proboscis with the mouth-parts at the end of the snout. 
The mouth-parts of such insects are like those of the locust 
and are therefore fitted for biting. 

Mouth-parts Fitted for Sucking. The mouth-parts of 
the locust have been described in some detail because the 
mouth-parts of sucking insects have all been developed by 
modification of the biting type. These modifications have 
proceeded in different ways in different groups, and are 
so characteristic and peculiar for each group that it Js 
possible for the students of insects to recognize the group 
to which any particular insect belongs by a study of its 
mouth-parts alone. Bees and wasps have one type ; the 
two-winged flies, as the mosquito, 
horse-fly, and house-fly, another ; 
the true bugs, as the cicada, stink- 
bug, and squash-bug, another, and 
the moths and butterflies still an- 
other. 

Bees and Wasps. The mouth- 
parts of these insects are usually 
stated to be of the sucking type ; 
they are in reality a combination . ^ 

of the two. Mandibles, Fig. 14 m d, Fw. 14'— Honey-bee. A, 
with sharp CUttin gedges are head of honey-bee show- 
usually present and fitted for '"5' mouth-parts extend- 

biting, the upper lip is small f.' ^' ~^"«« «^^^ '«- 

J . -,. ,. , .^ -n T bium enlarged. 

and indistinct, the maxillae and 

labium, Fig. 14 A, have been greatly elongated and 
find their greatest development in the honey-bee 
If the maxillae. Fig. 14 mx, of the honey-bee are 
compared with those of the locust, it is seen that the 
lacinia is wanting and the maxillary palpus, Fig. 14 
mp, is reduced to a mere tubercle. The greatest modi- 
fication is found in the labium ; the glossa, Fig. 14 g, in 





92 MANUAL OF GENEEAL AGEICULTUEE. 

the locust a mere rudiment, is longer than any other part, 
while the paraglossae, large flaps in the locust, are mere 
rudiments completely concealed by 
the base of the labial palpi, which like 
the glossa have been greatly elong- 
ated. The maxillae and labial palpi 
have been hollowed out on one side, 
and when closely appressed to the 
glossa form a tube for taking up 
liquids. Make a drawing of the head 
of a bee, showing mouth-parts. 

True Bugs. The mouth-parts of the ^^^ i5.-Squash-hug. 
true bugs are so different from those a, head and thorax 
of all other insects that there cannot viewed from side. B, 
be said to be any resemblance what- mouth -parts sepa- 
soever. Observe that when the head '"^'^ ""''^ enlarged. 
is examined from the side. Fig. 15, a slender tube is seen 
extending from the apex of the head along the under side 
of the body between and beyond the first pair of legs. 
This tube is the modified labium, Fig. 15 lb. It has a slit 
on the under side and consists of three or four segments. 
The slit is triangular in outline near the apex of the head ; 
it is filled by a triangular shaped labrum, Fig. 15 1, whieli 
completely closes this part of the tube. Both palpi and 
paraglossae are lacking. Contained within this tube are 
four bristle-like structures ; two of them represent the 
greatly modified mandibles, Fig. 15 d, and two of them 
maxillae. Fig. 15 mx. They are so changed in appearance 
that their identity was determined only by studying their 
development. The bristle-like mandibles and maxillae 
have at their apices fine teeth with which they can punc- 
ture the plant, and are usually of about the same length 
as the tube ; but in scale insects, as the San Jose scale, the 
tube is very short and the bristles are two or three times 
as long as the body. ]Make drawing showing these parts. 

Moths and Butterflies. The mouth-parts of a moth or 
butterfly when not in use are almost completely concealed. 
They are rolled up into a tight spiral like a watch-spring 



lEANUAL OF GENEEAL AGEICULTUEE. 



93 




Moth. A, 
head ivith maxillae 
slightly uncoiled. B, 
head loith maxillae 
imcoiled and the 
two maxillae sepa- 
rated at apex. C, 
cross section of 
maxillae to show the 
furroiv, f, formed 
by their appres- 
sion. 



on the under side of the head, Fig. 
16 A. They are not inconspicuous be- 
cause of their small size, for in the 
adults of many of the larger Sphinx 
moths they are nearly six inches long, 
but are concealed by the flattened 
scales which cover the body. The up- 
per lip or labrum is reduced to a mere 
rudiment, the mandibles or biting 
jaws are wanting, the lower lip or la- Fig. 16 
bium is represented by the labial 
palpi. Fig. 16 Ip, which are rigid and 
project up over and in front of the 
face. The coiled tube consists of the 
two maxillae, which have been greatly 
elongated and closely appressed to 
each other. Each maxilla is hollowed 
out or grooved on its inner surface, 
Fig. 16 C, and by the close apposition 
of these grooves a tube is formed 
through which liquid food can be drawn. JMoths and but- 
terflies obtain their food in great part from the nectar 
cups of flowers. In some moths the tips of the maxillae 
are armed with strong spines, with which they can lacer- 
ate the tissues of ripe fruits and set free their juices. 
Make drawings of the head of a moth as shown in Fig. 
16 A andB. 

The insecticidal poisons applied for biting insects 
have no effect therefore upon sucking insects, because the 
sucking insects puncture the plant tissue and feed upon 
the juices of the plant beneath the poisonous coating on 
the surface. Since the poison cannot be taken up with 
their food, it is not carried into their alimentary canal, 
and its application produces no changes in their life. 

Insects with Biting Mouth-parts: 
Grasshopper-like Insects : 

Crickets, katydids, meadow grasshoppers, locusts or grasshoppers. 



94 MANUAL OF GfENERAL AGRICULTUEE. 

Beetles : 

June bug or May beetle, Colorado potato beetle, lady bug, click 
beetle, flat-headed appletree borer, firefly, rosebug, striped cu- 
cumber beetle, cucumber flea beetle, pea weevil, blister beetle, 
plum curculio. 
Larvae : 

Larvae of beetles (grubs), larvae (caterpillars) of moths and 
butterflies, lar\'ae of saw-flies. 
Insects with Sucking Mouth-parts: 
True Bugs : 

Four-lined-leaf -bug, red-bug, bed-bug, chinch-bug, squash-bug, 
stink-bug, cicada, leaf hopper, aphids or plant lice, pear-tree 
psylla, San Jose scale. 
Moths and Butterflies: 

Codling moth, bud-moth, clothes-moth (larvae have biting mouth- 
parts), peach tree borer moth (larvae have biting mouth- 
parts), canker-worm moth, measuring-worm moth, cut-worm 
moth, tomato-worm moth, Cecropia moth, Polyphemus moth, 
Luna moth, tent caterpillar moth. Cabbage butterfly. Monarch 
butterfly. Viceroy butterfly, Eed Admiral butterfly. Mourning 
Cloak butterfly. 
Adults of two-winged flies: 

Mosquito, black fly, horse fly, syrphus fly, bot fly, house fly, horn 
fly, blow fly. 
Bees and Wasps: 

Yellow jacket, hornet, carpenter bee, bumble bee, leaf cutter bee, 
honey bee. 

Of the insecticides chief among the poisons are Paris 
Green and arsenate of lead. Among the contact remedies 
lime, sulphur and tobacco. Obtain without cost the third 
reference "Destructive Insects and Their Control" and 
experiment with one each of the two classes of insects 
found destructive to vegetation in your region. Every 
experiment station publishes literature on the control of 
insects within its State so that it is possible to obtain defi- 
nite information about almost any destructive insect. 

PART VI. TESTING MILK AND ITS PRODUCT. 
70. EXPERIMENTS WITH MILK. 
Materials: Milk, microscope, litmus paper, rennet, 
two evaporating dishes, dilute acetic acid. 

(a) Examine a drop of milk with a microscope. 
Make a drawing. 

(b) Test the reaction of milk with litmus paper. 



]V[ANUAL OF GENERAIi AGRICULTURE. 95 

(c) (1) Warm some milk in a test tube to a tem- 
perature of the body (98° F.) and add a few drops of 
rennet. A curd of casein is soon formed. 

2. Repeat (1), but boil the rennet first. What effect 
does boiling have on the rennet or enzyme? 

(d) Place 20 c.c. water in an evaporating dish and 
20 c.c. milk in another evaporating dish. Heat both 
equally near the fire to boiling. Which boils first? What 
does this show about the boiling point of milk compared 
to that of water? Notice the scum which formed on the 
boiled milk. Remove it and heat the milk again. Result? 
What is the nature of this scum? The formation of this 
scum is not a true coagulation. 

(e) To about 10 c.c. milk add one drop of dilute 
acetic acid and boil. The casein is coagulated and brings 
down with it the fat. This is a true coagulation. 

71. ANALYSIS OF MILK. 

Materials : Milk, 2 beakers, cylinder or large beaker, 
watch crystal, water bath, acetic acid, filter, filter paper, 
alcohol, stirring rod, ether, crucible, scales. 

(a) 1. Weigh a small beaker, place 50 c.c. of milk 
in it and weigh again. Subtract and the difference in 
weight equals the weight of milk taken. Record this 
weight. 

Pour the 50 c.c. of milk into a large beaker or cylin- 
der and add 100 c.c. of distilled water. Rinse out the 
small beaker with 100 c.c. more of distilled water and 
add to the beaker or cylinder. Be sure the small beaker 
is well rinsed. Mix well and while stirring gently, add 
dilute acetic acid (1-10) drop by drop, until the precipi- 
tate stops forming. Test this by transferring a drop of 
the liquid to a watch crystal, adding a drop of acetic 
acid. If no precipitate forms, the solution is ready to set 
aside over night. This precipitate contains casein and 
fat. Milk sugar and albumen are in the water solution. 

2. Filter and remove all the casein after it has set 
over night and save filtrate. Drain carefully, squeeze out 
water from the filter paper into filtrate. Transfer this. 



96 MANUAL OF GENERAL AGRICULTURE. 

wet precipitate to a small dry beaker and add 30 c.c. of 
alcohol and stir. Filter a second time and squeeze filter 
paper as dry as possible. Transfer the precipitate to an- 
other small beaker and add 50 c.c. ether. Heat on a 
water bath a little warmer than milk warm, ten minutes, 
stirring constantly. Filter and save both precipitate and 
filtrate. The precipitate is the casein. Spread open the 
paper in order for the ether to evaporate and allow it to 
dry. Place the dried casein in a weighed dish and weigh. 
The difference in weights equals the weight of casein. 

To get the per cent of casein in the milk, divide the 
weight of the casein multiplied by 100 by the weight of 
milk taken in the beginning, thus : 

grams casein -mn /^v • ■ -n 

° . X 100=% casein in milk. 

grams milk 
The filtrate contains the fat dissolved in ether. Evap- 
orate the ether by placing the beaker over a heated water 
bath and the fat will be left. Weigh and the difference 
between weight of beaker plus fat and weight of beaker, 
equals the weight of fat. Get per cent of fat in milk 
by dividing the weight of fat multiplied by 100 by the 
weight of milk taken in the beginning, thus: 

g"^"^^ ^^.^ X 100=% fat. 
grams milk 

The ether dissolved the fat out of the casein. Casein 
is not soluble in ether. 

Go back to the first filtrate (after you filtered off the 
acetic acid from the casein.) Throw away half the solu- 
tion or save for a second trial and evaporate the other 
half over a flame. This contains the water, milk sugar, 
lactic acid, and albumen. As you heat the solution, note 
the coagulation of the albumen. When the albumen has 
coagulated, filter. Evaporate the filtrate to dryness, but 
do not burn it. Sugar will be left. Test with Fehling's 
solution. (See Exercise 37, a.) Does the milk sugar crys- 
talize readily? 

(b) To find per cent of solids and ash in milk. 
Weigh 5 c.c. milk in an evaporating dish. Evaporate it 
over the flame carefully, taking care not to blacken it, as 



MANUAL OF GENERAL AGRICULTURE. !)7 

some carbon would be consumed as carbon dioxid. Fin- 
ish evaporating in a water bath, then heat in an oven at 
100° C. or 212° F. for fifteen minutes. Cool and weigh. 
Place again in the oven for fifteen minutes. Cool and 
weigh, and if the two weights are the same, get per cent by 
dividing the weight of the milk after water is evaporated 
out by the weight of the milk taken. The result will be 
the per cent of total solids in the milk. What is the per 
cent of water? Transfer to a clean crucible and place 
over a flame and burn off the organic material. Burn 
until the ash is perfectly white. Cool and weigh. Divide 
the weight of the ash by the weight of milk taken and the 
result is the per cent of ash in the milk. This ash con- 
tains the mineral salts. Save for the next experiment. 

72. TESTS FOR THE MINERAL SALTS IN THE ASH 
OF MILK. 

Sodium and Potassium. Treat 1 -3 the ash of milk ob- 
tained in the previous experiment with 10 c.c. distilled 
water. Filter and test 1-3 the filtrate with litmus to see 
if it is neutral. Dip a platinum wire in this 1-3 and test 
for potassium and sodium in the flame. Use purple glass 
for potassium as in the presence of sodium, potassium can- 
not be seen. 

Chlorids. Test the second portion of the distilled 
water solution for chlorids by acidifying with a few drops 
of nitric acid, and adding one drop of silver nitrate solu- 
tion. A white cloudiness shows chlorids. 

Iron. To the remainder of the distilled water solution 
add a few drops of hydrochloric acid. Add a few drops 
of potassium ferrocyanid. Let stand a few minutes. A 
blue color shows iron. 

Calcium and Magnesium. Take the second portion of 
ash and add 10 c.c. warm hydrochloric acid. Note if any 
gas is given off. If so carbonates are present. To the 
hydrochloric acid solution, add ammonium hydroxid un- 
til alkalin. (Test with litmus.) Add an equal amount 
of ammonium oxalate and heat to boiling. A white pre- 
cipitate shows the presence of calcium. Filter this and 



98 MANUAI. OF GENERAL AGRICULTURE. 

to the filtrate add a little acid sodium phosphate, A 
white precipitate shows magnesium. 

Phosphates. To the remainder of the ash add nitric 
acid until acid and add twice its volume of ammonium 
molybdate solution. Allow to stand. A fine yellow pre- 
cipitate or color shows phosphates. Place in a table the 
minerals found in milk. 

73. CALIBRATION OR CORRECTION OF GLASS- 
WARE. 

Materials: Mercury, scales, milk, and cream test 
bottles. 

The correctness of the graduation of glassware may 
be most conveniently and accurately tested by the folloAv- 
ing method : 

(a) Milk Test Bottles. Weigh 27.10 grams of mer- 
cury into a perfectly clean and dry milk test bottle. Since 
the specific gravity of mercury is 13.55 or 1 c.c. weighs 
13.55 grams, double this weight will occupy a volume of 
exactly 2 c.c. Close the neck of the milk test bottle with 
a small, smooth, soft cork, or a wad of absorbent cotton 
cut off square at one end. Press this stopper down to the 
first line of the graduation, then invert the bottle so that 
the mercury will run into its neck. If the total space 
included between and 10 marks is just filled by the 2 
c.c. of mercury, the graduation is correct. 

The mercury may be conveniently transferred from 
one test bottle to another by means of a thin rubber tube 
which is slipped over the ends of both bottles and one 
weighing of mercury will thus suffice for a number of 
calibrations. 

Mercury may be cleaned from mechanical impurities, 
dust, water, etc., by filtration through heavy filter paper. 
This is folded in the usual way, placed in an ordinary 
glass funnel and its point perforated with a couple of pin 
holes. The mercury will pass through in fine streams, 
leaving the impurities on the filter paper. 

(b) Cream Test Bottles. The cream test bottles may 
be calibrated by the method given for milk bottles. The 



IVtANUAL OF GENEEAL AGEICULTUEE. 99 

neck of a cream bottle that measures fifty per cent fat will 
hold 10 c.c. or 135.5 grams of mercury. 

(c) Pipette and Acid Cylinder. In calibrating the 
pipette sufficiently accurate results may be obtained by 
weighing the quantity of water which the pipette will de- 
liver, viz., 17.5 grams. A measureful of water may be 
emptied into a small vessel, weighed, and this vessel 
weighed a second time. The weight of the water con- 
tained in the pipette is the difference. 

Calibration of the acid cylinder is not necessary since 
small variation in the amount of acid measured out does 
not affect the accuracy of the test. In calibrating any of 
the glassware water instead of mercury may be used, but 
is less satisfactory and not in such general use. 

74. DETERMINATION OF THE STRENGTH OR SPE- 
CIFIC GRAVITY OF SULPHURIC ACID. 

Materials: Milk test bottle, scales, sulphuric acid to 
be used in the Babcock test, acid hydrometer (See b.) 

(a) Weigh a dry test bottle and then fill with acid 
exactly to the zero mark. "Weigh again accurately and 
the difference between the two weights will give the 
weight of the acid. Empty the bottle and thoroughly 
rinse with water. Wipe the outside dry. Fill with water 
to the zero mark as before and weigh. The difference be- 
tween this weight and that of the empty bottle gives the 
weight of the water. Calculate the specific gravity by 
dividing the weight of the acid by the weight of the 
water. If the quotient is between 1.82 and 1.83 the acid 
is of correct strength. 

If the acid is a little too strong, later in making tests 
take less than the required amount, perhaps, about 16 c.c. 
If too weak add a litle more than 17.5 c.c. If the acid 
is too strong the better way to do is to pour the acid into 
a bottle containing a small quantity of water. Never 
dilute sulphuric acid by pouring water into the acid as 
the acid may be spattered. For more accurate results the 
temperature of the acid should be 60°F. 



100 MANUAL OF GENERAL AGRICULTUP-E. 

(b) A shorter method is by the use of an acid hydro- 
meter. When an instrument of this kind is used it is only 
necessary to lower it into the acid and read off the specific 
gravity. 

75. THE BABCOCK TEST OF MILK. 

Materials: Half pint of milk (enough for entire 
class), 17.6 c.c. milk pipettes, milk test bottles, water- 
white sulphuric acid of specific gravity between 1.82 and 
1.83. Vessel for heating water, small beaker, dividers, 
(the latter desirable but not necessary) and Babcock 
tester, distilled or soft (rain) water. 

(a) Sampling the Milk. Be careful that the sample 
represents a fair average to be tested. Any cream that 
may rise on the milk should be thoroughly mixed with the 
milk by cautiously pouring back and forth from one vessel 
to another. 

(b) Measuring Milk. This is done with a milk pipette 
which holds when filled to the mark on the stem, 17.6 cc. 
Suck the milk up into the pipette above the mark and 
place the finger quickly on the upper end of the pipette, 
then press firmly down to keep the milk from running 
out. Hold the pipette vertically with the mark on a 
level with the eye and by gently relaxing the pressure of 
the finger on the end of the pipette, air is admitted and 
the milk is allowed to flow slowly out until the top of the 
column of the milk is level with the mark of tlie pipette. 
Read it to the lowest part of the curve or meniscus. The 
pipette then holds 17.6 cc. of milk. 

(c) Filling the Test Bottles. Place the point of the 
pipette into the mouth of the milk test bottle, holding 
both milk test botle and pipette in an inclined position. 
By removing the finger from the end of the pipette the 
milk will flow out of the pipette and into the bottle. 

The object of inclining the test bottle and pipette is 
to allow the milk to run down the side of the neck of 
the test bottle, thus allowing the exit of the air in the 
bottle. If this precaution is not observed, the air will 
bubble out and cause some of the milk to overflow. 



MANUAL OF GENEEAL AGRICULTURE. 101 

Allow the pipette to drain into the test bottle and blow 
into the upper end of it to discharge the last drop of 
milk in the pipette into the test bottle. 

The best results will be obtained by having the 
samples of milk and also the acid at the temperature of 
60° F. 

Find the ground or frosted part on the body of the 
bottle and place on it your initials ; or better still ask 
the teacher to give you a number corresponding to a 
number by the side of one of the receptacles in the tester. 
Always use the same number and the same bottle in order 
to avoid confusion. 

(d) Adding the Acid. After the milk has been meas- 
ured into the test bottles, the acid should be added. This 
may be done at once or the milk may be allowed to stand 
in the test bottles for a number of days without clianging 
the results. Fill the acid measure up to the mark (17.5 
c.c.) with sulphuric acid of the specific gravity l)etween 
1.82 and 1.83. To pour the acid into the test bottle, 
the bottle should be placed in an inclined position so 
that the acid will flow down the side of the test bottle 
and not drop through the body of the milk in the bottle. 
By observing this precaution, charring of the milk is 
avoided and also spilling out of the acid. If the acid 
has been properly added, there will be distinct layers of 
acid and milk in the test bottle, without any black layers 
mixed between them. 

(e) Mixing the Milk and Acid. This is done by giv- 
ing the test bottle a combined rotary and shaking mo- 
tion, being careful not to allow any curd to get into the 
neck of the bottle. The shaking of the bottle should be 
continued until all the particles or clots of curd are en- 
tirely dissolved. The liquid will then be a dark brown 
color and of a high temperature, due to the chemical ac- 
tion of the acid on the milk. The object of adding the 
acid is to dissolve all the solids in the milk, except the 
fat which is left in suspension in the liquid. 

Caution. The acid is very corrosive and should not 
be allowed to get upon the person or clothes. If any 



102 MANUAL OF GENEEAL AGRICULTUEE. 

should be spilled on the skin or clothing, it should be 
quickly washed off with water. Color can be restored 
to clothing by treating the spot at once with ammonia 
water. 

(f) Whirling the Bottles. Place the test bottles with 
the milk and acid properly mixed in the tester or centri- 
fugal machine. The bottles should be arranged in pairs 
at the opposite side of the center, so that they will balance 
when rotating. It is better to put the bottles into a tester 
directly after mixing the milk and acid, while the bottles 
are hot. If, however, this should not be convenient, the 
bottles may be allowed to stand an indefinite period, but 
when they are placed in the machine, means should be 
provided for heating them while rotating so as to keep 
the fat in a melted condition. This is done in the steam 
machine by turning on a steam jet provided for that pur- 
pose or in the hand machine by placing boiling water in 
the bottom of the tester and putting on the cover at once 
to retain the steam. The bottles should be whirled for 
five minutes at the speed marked on the machine, and 
then the machine allowed to slowly come to rest for the 
purpose of adding hot water. 

(g) Adding Hot Water. The object of adding hot 
water is to bring the fat up into the graduated portion 
of the neck where it can be measured. Boiling hot water 
should be added by means of the pipette or a beaker. 
Perfectly clear readings can be insured by adding the 
water in two installments. First, add enough hot water 
to bring the fat to, but not into, the neck of the bottle, 
then whirl for two minutes. Stop, and add enough hot 
water to bring the fat into the graduated part of the 
neck, adding the water gradually so as not to overflow 
the fat. Whirl a third time for one minute. With this 
method a beautifully clear reading should result with a 
layer of clear water below the fat. If the reading of the 
fat is at all cloudy add a little hot water and whirl again. 
It is desirable to use distilled water, rain water, or soft 
water of any kind. 



MA.NUAL OF GENERAL AGRICULTUEE. 103 

(h) Reading the Test. The fat, if the bottles have 
been kept at a proper temperature, will be liquid and will 
be level or right angled to the neck of the bottle at the 
ends of the fat column. To read the per cent fat, hold 
the bottle up with the fat on the level with the eye and 
read the graduations at each end of the column of fat. 
Make a liberal reading by including the upper and lower 
meniscus in the reading. Each small division represents 
two tenths of one per cent of fat and the large spaces 
numbered 1, 2, 3, etc., to 10, represent one per cent of 
fat each. By subtracting the readings taken, the per- 
centage of fat is obtained. Thus if the top of the fat 
column is at 7.4 and the bottom at 2.6 the reading is 7.4 
less 2.6 equals 4.8 per cent fat, which means that in 100 
lbs. of milk there are 4.8 lbs. of fat. The reading may be 
more easily done by using a pair of dividers. 

(i) Washing the Test Bottles. This is done most 
easily if the bottles are emptied at once after making the 
test and while hot. They should be given a rotary mo- 
tion which allows the air to enter and empties them 
quicker, besides carrying off the sediment that is on the 
bottom of the bottles. Rinse thoroughly with boiling 
water to remove the grease, dirt, and acid solution from 
the inside. Occasionally boil the bottles in water con- 
taining a little cleaning powder. 

76. THE BABCOCK TEST OF CREAM. 

Materials: Babcock tester and accompanying ap- 
paratus, cream, two fifty per cent test bottles. 

In testing cream inaccurate results will be obtained 
if 17.6 c.c. cream is measured out in a pipette as in the 
case of milk. In the first place the specific gravity of 
cream is lower than that of milk. The specific gravity of 
20% cream will be considerably more than 40% cream. 
Also cream will adhere more to the sides of the pipette 
than milk. Hence accurate tests of cream can only be 
made by weighing the cream in the Babcock test bottle. 

Place a cream test bottle on each side of the scales 
and see that they are accurately balanced. Place 18 



104 MANUAL OF GENEEAL AGEICULTUEE!. 

grams in weights on one side. Take the sample of cream 
to be tested and warm it by shaking the cream and vessel 
in a pail of water as hot as the hand will bear for one or 
two minutes. (The cream should not rise above 90° F). 
Mix by pouring from one bottle to another four or five 
times. Suck up the cream into the milk pipette until 
the upper level is an inch or so above the 17.6 c.c. mark. 
Gradually let it run into one of the bottles until the 
scales just balance. Remove the weights, leave both 
bottles on, and in a similar manner pour cream from the 
same sample, or another sample to be tested, into the 
empty bottle on the other side until the scales just 
balance. Add the acid and complete the test the same as 
for milk. 

Unless the reading is done quickly the bottles should 
be placed in water from 140° to 150° F., the water rising 
nearly to the top of the necks. Let them remain there 
five minutes, then perfectly clear readings can be ob- 
tained. This is necessary when several samples are to 
be tested by one operater, as the fat will contract from 
the cold and slip down the neck before all can be read. 

77. THE BABCOCK TEST OF SKIM MILK. 

Materials: Skim milk bottle, 17.6 cc. pipette, acid 
cylinder, sulphuric acid, half pint of separator skim milk. 

The Babcock test of skim milk, butter milk, and 
whey is the same as that of milk except as indicated in 
this experiment. 

A double necked test bottle is made especiallj^ for 
measuring small amounts of fat. The smaller neck will 
measure .25 of one per cent, each of the smaller gradua- 
tions representing .01 of one per cent. 

To make a test measure out 17.6 c.c. of skim milk 
with a pipette as was done with milk and then pour it 
into the larger neck of the skim milk bottle. Next slowly 
add the sulphuric acid, but instead of using 17.5 c.c. of 
acid use 20 c.c. Place in the tester with the filling, tube 
toward the center. Whirl and add water in the usual 
manner, but it is highly desirable to use either distilled or 



MANUAL OF GENERAL AGRICULTURE. 105 

rain water. Make a liberal reading as in the case of milk. 
Some difficulty may be encountered in getting the smaller 
amount of fat within the scale. This may be overcome 
by putting a cork into the neck of the large opening and 
gently working it up and down so that it will be possible 
to regulate the position of the fat. Make a reading as 
quickly as possible or the fat may adhere to the inside of 
the neck as a film of grease which cannot be measured by 
the scale. A test of .02 of one per cent shows an efficient 
separation. 

A test of skim milk showing no fat in the neck of the 
test bottle on completion of the test generally shows poor 
work on the part of the operator and should be repeated. 

Obtain some butter milk and also some whey and 
test each the same as skim milk except that in the case 
of whey 17.5 c.c. of acid is sufficient since whey contains 
less solids not fat for the acid to dissolve. 

78. THE LACTOMETER AND ITS APPLICATION. 

Materials: Quevenne lactometer, 500 c.c. cylinder, 
pint of milk, pint of skim milk. 

The specific gravity of normal cow's milk will vary 
in different samples between 1.029 and 1.035 at 60 degrees 
F., the average being about 1.032. The lactometer is 
used for determining the specific gravity of milk. There 
are two in use : the Quevenne and the Board of Health. 
Only the Quevenne will be considered. 

The Quevenne lactometer consists of a hollow cylinder 
weighted by means of mercury so that it will float in 
milk in an upright position, and provided with a narrow 
stem at its upper end, inside of which is found a grad- 
uated paper scale. A thermometer is placed in the cylinder 
with its bulb at the lower end of the lactometer and its 
stem rising above the lactometer scale. The scale is 
marked at 15 and 40, and divided into 25 equal parts, 
with figures at each five divisions of the scale. The single 
divisions are called degrees. The fifteen degree mark 
is placed at the point to which the lactometer will sink 
when lowered into a liquid of a specific gravity of 1.015 



106 MANUAL OF GENEEAL AGRICULTUEE. 

and the 40 degree mark at the point to which it will sink 
when placed in a liquid of a specific gravity of 1.040. 
To mix thoroughly pour the sample to be tested from one 
receptacle to another then fill a 250 c.c. or larger cylinder 
about three fourths full. Carefully lower the lactometer 
into the cylinder until it floats. In about half a minute 
take the lactometer reading and the temperature read- 
ing. In reading the lactometer degrees the mark on 
the scale plainly visible through the upper portion of 
the meniscus should be noted. When the lactometer de- 
gree is known, the corresponding specific gravity is found 
by dividing by 1000 and adding one to the quotent. 

Example: If the lactometer reading is 34.3 and the 
temperature 60°, the specific gravity is 34.3-^1000:^.0343; 
.0343 plus 1=1.0343. 

Like most liquids milk will expand on being warmed, 
and the same volume will weigh less when warm than 
before ; i. e., its specific gravity will be decreased. There- 
fore the lactometer is standardized to 60°. It is incon- 
venient to always have milk at exactly this temperature. 
By making a temperature correction milk between 50° 
and 70° may be tested, but outside of a range of 10° on 
either side of 60° the test will be inaccurate. To make 
the temperature correction add .1 to the lactometer read- 
ing for each degree above 60°F., and subtract .1 for each 
degree below 60° ; e.g., if the reading at 63° is 33.6 it will 
be 33.6 plus .3=33.9 at 60°. The specific gravity would 
then be 33.9 divided by 1000=.0339. .0339 plus 
1=1.0339. If the reading is 30 at 54° the corrected 
reading will be 30— .6=29.4. 

Test the specific gravity of a sample of skim milk 
and of a sample of milk with a small amount of water 
added. 

Question: 1. Under what conditions would it be 
difficult to detect adulteration with water? 

2. When could the presence of water be easily de- 
tected? 



MANUAL OF GENEEAL AGEICULTUEE. 107 

79. TESTING THE ACIDITY OR SOURNESS OF 

MILK AND CREAM. 

Materials: Samples of milk and cream, 50 c.c. bu- 
rette* provided with stopcock, 17.6 c.c. pipette, a tin, 
porcelain or glass cup, % gallon neutralizer, indicator. 

"With a 17.6 c.c. pipette measure into a clean cup this 
amount of milk and add a few drops of indicator. Attach 
the burette to a ring stand and fill with the alkali solu- 
tion nearly to zero mark. Read accurately the top of 
the column. Next cautiously add the neutralizer from 
the burette. By constant stirring during the operation 
it will be noticed that the pink color formed by the addi- 
tion of even a drop of alkali will at first entirely dis- 
appear, but as more and more of the acid in the sample 
becomes neutralized, the color will disappear more slowly, 
until finally a point is reached when the pink color re- 
mains permanent for a time. No more alkali should be 
added after the first appearance of a uniform pink color 
in the sample. Take a second reading of the column. 
Ascertain the amount of alkali solution used by subtract- 
ing the readings of the scale on the burette. The per 
cent of acidity may be obtained by dividing the number 
of c.c. used by 20. The result will be the per cent of 
acidity in tenths. For example if 17.6 c.c. of milk re- 
quired 3 c.c. of alkali solution to give a pink color the 
per cent of acid is 8-i-20=.4%. 

80. CALCULATION OF THE PERCENTAGE OF 

MILK SOLIDS. 

Materials : One or two pint samples of milk, cylinder, 
lacometer, Babcock tester and accompanying materials. 

The calculation of milk solids can be easily done by 
using the following formulas : 

Per cent of Solids not fat^i/4L+.2f. 

Per cent of Total Solids=i4L+1.2f. 

*In the Marshall Acid Test the per cent acidity can be read 
directly. If no burette is at hand the outfit for this test had 
better be purchased. 



308 • MANUAL OF GENERAL AGRICULTURE. 

L being the lactometer reading at 60°F or corrected 
for temperature, and f the per cent of fat in the milk. 

Example. If the lactometer reading (L) is 31.2, 
the temperature (T) is 64° and the per cent of fat (f) 
is 3.6 the calculation of Solids not fat is as follows: 
31.2-f-.4=31.6, the corrected lactometer reading, adding 
.1 for every degree over 60°. 

Per cent of solids not fat=i4L-|--2f, 

=i4x31.6+.2x3.6 
=7.9+.72=8.62% 
Per cent total solids =i4L+1.2f, 

=7.9+4.32=12.22% 
Or for per cent of total solids simply add the fat 
to the solids not fat as 8.62+3.6=12.22. 

81. TEST FOR PHYSICAL ADULTERATION 
OF MILK. 

Materials: Lacometer, Babcock tester, normal, 
watered, skimmed, and watered-and-skimmed milk. 

Milk may be adulterated by being watered, skimmed, 
or both watered and skimmed. 

If the analysis of the suspected sample shows 

sp. gr. of milk ) j^^, ) 

fat and solids not fat ) > watered 

sp. gr. of solids normal ) 

sp. gr. of milk and of solids... L . , ) 

solids not fat ' ^^ )• skimmed 

fat and solids low ) 

sp. gr. of milk normal ) watered 

sp. gr. of solids normal or high > and 

fat and solids not fat low ) skimmed 

Latitude of variation. 

Specific gravity of milk may vary from 1.029 to 1.035. 
Fat must not fall below 3. 

Solids not fat must not fall below 9. (in most states.) 
Specifie gravity of solids may vary between 1.25 and 
1.34. 



MANUAL OF GENERAL AGRICULTURE. 109 

The specific gravity of (milk) solids is determined by 

t 

the following formula : S= 

100s— 100 

t 



s 
S being the specific gravity of the milk solids, s that of 
the milk and t the total solids of the milk. 

Example: A sample of milk has been found to con- 
tain 13. per cent of total solids, sp. gr. 1.032 ; then 
100s— 100 100x1.03^—100 

= =3.101; t— this or 13.-3.101 

s 1.032 

13. 

=9.899 ; then dividing t by this, =1.31, the specific 

9.899 
gravity of milk solids. Let the teacher furnish samples 
of normal, watered, skimmed and watered-and-skimmed 
milk and the class determine each. 

82. TEST FOR CHEMICAL ADULTERATION OF 
MILK. 

Materials: Salicylic acid, formalin in samples of 
milk, ether, surphuric acid, alcohol, iron chlorid solution, 
hydrochloric acid, evaporating dish. 

(a) Salicylic Acid. To 20 c.c. of milk add from 2 
to 3 c.c. sulphuric acid and 4 to 5 c.c. ether and stir in 
an evaporating dish. Evaporate and treat the residue 
with about 3 c.c. alcohol, add a few drops of iron chlorid 
solution and heat again. A deep violet color will be ob- 
tained in the presence of salicylic acid. 

(b) Formalin (Formaldehyde). To one-fourth test 
tube of milk add an equal volume of water and 5 to 10 
c.c. sulphuric acid used in testing. A violet ring is formed 
at the junction of the two liquids if formalin is present ; 
if not, a slight greenish tinge will be seen. The violet 
color is not obtained with milk containing over .05 per 
cent formalin. 



110 MANUAL OF GENERAL AGEICULTURE. 

(c) Formalin (optional). 

To 10 c.c. of milk in an evaporating dish add an equal 
volume of hydrochloric acid. Add one drop of ferric 
chlorid solution, heat gently, stirring until contents are 
nearly boiling. The formaldehyde turns the casein of the 
milk violet. If no formalin is present the liquid turns 
brown only. 

83. DETERMINATION OF MOISTURE IN BUTTER. 

Materials: 300 c.c. aluminum cup, butter to be tested, 
ring stand, spatula or spoon, fine wire or thread, scales, 
alcohol lamp. 

Anyone who is familiar with testing of butter for 
moisture is well aware of the fact that an accurate test is 
not possible unless the sample taken for testing is a repre- 
sentative one. In view of the heavy penalties imposed be- 
cause of excessive moisture, no buttermaker can afford to 
do the work ignorantly or carelessly. The matter of 
proper ways of taking samples and of testing is as yet 
more or less unsettled, but the following suggestions are 
generally recognized as being worthy of attention. 

In taking a sample from the churn, remove a portion 
of the surface of the butter at vairous places of the churn, 
and by means of a spatula or spoon take out small pieces. 
Butter in the churn contains many water pockets and 
these must be avoided, as they are worked out in packing. 

In taking a sample from the print use a fine wire or 
thread as butter can be easily cut in this way. Several 
small slices from different parts of the print are sufficient. 
As fast as the slices are made, place them in an ordinary 
pint fruit jar and after they are all in it, screw the cap 
down air-tight. 

Samples taken as above are approximate representa- 
tives only, so that in order that the parts taken may be- 
come a uniform mixture, it is necessary that they be 
melted at as low a temperature as possible (not above 
120° F.) in order that none of the volatile substances pass 
off as vapor. This may be done by placing the sealed sam- 
ple in a pail of water as hot as the hand will bear and 



MANUAL OF GENEEAL AGEICULTUBE. Ill 

allowing it to remain there a few moments, shaking occa- 
sionally, until the butter is melted. Cool until solid, shak- 
ing often to insure an even distribution of the constit- 
uents. 

Special scales for moisture testing are on the market, 
but any sensitive scales will do. 

See that the scales are accurately balanced. The 
aluminum cup is capable of taking up moisture from the 
air and for this reason must be heated a moment or two 
until perfectly dry and at once accurately weighed. When 
the scales balance with the beaker on, write down the 
weight of the beaker and then place a 10 gram weight on 
the side opposite the beaker. 

Take the sample of butter, remove the cover, and 
with a spoon place butter in the beaker until the scales 
exactly balance, giving a ten gram sample. 

Heat the sample until all the moisture is evaporated. 
A direct flame as that of an alcohol lamp is satisfactory, 
but care must be taken not to burn the butter. By shaking 
two or three times with a rotary motion, the burning of 
the butter may be prevented. 

After sputtering has ceased, weigh. Heat a second 
time and if the weights are the same upon reweighing, all 
the moisture has been driven off. If the two weights are 
not the same, heat the third time and weigh again and 
continue to reheat and reweigh until a constant weight is 
obtained. 

Record results and calculate the per cent of moisture 
as follows : 

Weight of beaker 38.5 grams 

Weight of beaker and butter 48.5 grams 

AVeight of beaker and butter after heating 47. grams 

Weight of butter after heat 8.5 grams 

Loss 10 — 8.5 1.5 grams 

(1.5-f-10)xl00=15% moisture in the sample. It is illegal 
to sell butter containing more than 16% moisture. 



112 MANITAL OF GENERAL AGRICULTURE. 

84. DETERMINATION OF SALT IN BUTTER. 

Materials: Burette with stopcock, white cup, sat- 
urated solution of potassium dichromate, silver nitrate 
solution made by adding 14.531 grams of silver nitrate to 
1000 c.c. of distilled water. Butter to be tested, small bot- 
tle with cork or cover, 250 c.c. Florence flask with the 
250 c.c. height marked with a file. 

Melt about two ounces by guess of butter in a small 
covered bottle as was done in testing for moisture. Weigh 
into the Florence flask exactly ten grams of the melted 
sample, then add enough rain water of a temperature of 
about 140° F. to make 250 c.c. Shake thoroughly several 
times to dissolve the salt. Take 25 c.c. (best obtained 
with a 25 c.c. pipette) of the brine solution thus prepared, 
place it in the cup and add 2 or 3 drops of potassium 
dichromate as an indicator. 

Place the silver nitrate solution in a bruette arranged 
as in testing for the acidity of milk. Gradually let it run 
into the cup until a permanent pink color remains upon 
being thoroughly stirred. Note the number of c.c. of sil- 
ver nitrate used. Divide this number by the factor 2. The 
result is the per cent of salt in the sample. As salt is much 
cheaper than butter fat it is to the advantage of the butter 
maker to add about as much as the market will bear. 
Three per cent may not be too much. 

85. DETERMINATION OF THE PER CENT OF FAT 
IN ICE CREAM. 

Materials: Glacial acetic acid, sulphuric acid, ice 
cream, Babcock tester, and milk test bottle. 

Weigh nine grams of the melted sample into a Bab- 
cock milk bottle. Fill almost to the neck with a mixture 
of glacial acetic acid and sulphuric acid, using equal vol- 
umes of each. Heat a few minutes until black, then whirl 
in the tester for five minutes. Add water to bring the fat 
column within the graduation of the neck as in the regu- 
lar Babcock test. The reading multiplied by two gives the 
per cent of fat in the ice cream since the bottle is gradu- 
ated for 18 grams and only 9 grams were used. 



MANUAL OF GENERAL AGRICULTURE. 113 

If sulphuric acid alone is used it is likely to char the 
sugar in the ice cream, thus giving difficulty in reading 
the results. 

Ice cream should contain not less than twelve per cent 
of milk fat. 

Fruit ice cream and nut ice cream should contain not 
less than ten per cent of milk fat. 

86. STANDARDIZATION OF MILK AND OF CREAM. 

Materials: Half gallon of milk testing 4% or over, 
iy2 quarts of skim milk, Babcock tester and accompany- 
ing materials. 

]\lilk or cream is "standardized" or brought to any 
required test by the addition of skim milk, milk, or cream, 
according to the conditions. Standardization is perhaps 
most often a lowering of the butter fat test to just meet 
the requirements imposed by law. 

The ordinance of the city of Los Angeles requires at 
least 3.5 per cent butter fat. Probably most of the milk 
produced for Los Angeles consumption will test 4% or 
more. 

Example. Standardize 300 pounds of 4% milk to 
3.5%, using skim milk testing .1%. 

300 lbs. of 4 3.4* 300 : 3.4 



X lbs. of . 1 




Then as 



Solving, 300:3.4::X:.5 
3.4X=150 
X=44.1 
*The 3.4 and .5 are obtained by subtracting diagonally. 

Therefore to get the standard of 3.5% we must add 
44.1 lbs. of skim milk. 
Proof: 300 lbs. of 4% milk=12 lbs. of fat. 

44.1 lbs, of .1% skim milk=.04 lbs, of fat. 
344.1 lbs. of 3.5% milk=12.04 lbs. of fat. 
Obtain a half gallon of milk testing 4% or over and 
a half gallon of skim milk. Test each for butter fat. 



114 MANUAL OF GENEEAL AGEICULTURE. 

Weigh the milk. Calculate the number of pounds of skim 
milk that must be added to bring the milk to the standard 
of 3.5%. (Figure on a test of 3.6 since it is unsafe to risk 
selling milk at exactly the standard as some of the milk 
delivered may fall below.) Add the calculated amount of 
skim milk, then test the standardized milk to see if it 
tests 3.6. 

REFERENCES FOR CLASS STUDY. 
The first books in the list for each part will be found 
more satisfactory for high school work. 

Parts I and II 

Fletcher, S. W.— Soils. 

Snyder, H. S. — Soils and Firtilizers. 

King, F. F.— The Soil. 

Roberts, I. P. — Fertility of the Land. 

Voorhees, E. B. — Fertilizers. 

Hopkins, C. G. — Soil Fertility and Permanent Agri- 
culture. 

Hilgard — Soils. 

The Soil Bulletins of the U. S. Department of Agri- 
culture. 

Bailey, L. H. — Cyclopedia of American Agriculture. 

Part III 

Snyder, H. S. — Chemistry of Plant and Animal Life. 
Bailey, E. H. S. — Sanitary and Applied Chemistry. 
Snyder, H. S. — Chemistry of Plants. 
Bulletins of the U. S. Department of Agriculture. 

Part IV 

Wickson, E. J. — California Fruits and How to Grow 
Them. 

Bailey, L. H. — Principles of Fruit Growing. 

Warren, G. F. — Elements of Agriculture. 

Waugh, F. A. — Systematic Pomology. 

Hume, H. H. — Citrus Fruits and Their Culture. 

Lodeman, E. G. — Spraying Plants. 

Osterhout, W. J. V. — Experiments with Plants. 



MANUAL OF GENERAL AGRICULTURE. 115 

Bailey, L. H. — Pruning Book, Horticulturists' Rule 
Book, Nursery Book. 

Bulletins of the U. S. D. A. 

Part V 

"Warren, G. F. — Elements of Agriculture. 

Bulletin 218, California Plant Diseases, Agricultural 
Experiment Station, Berkeley, Cal. 

Destructive Insects and Their Control — Cal. State 
Board of Horticulture, Sacramento, Cal. 

Duggar, B. M. — Fungous Diseases of Plants. 

Part VI 

Wing, A. H.— Milk and Its Products. 

Farrington and Woll — Testing iMilk and Its Products. 

Van Slyke— Testing Milk. 

Van Norman, H. E. — First Lessons in Dairying. 

Bulletins of the U. S. D. A. 



LEFe'13 



OCT 'i\ »y»^ 



Nanual 

of 

General Agriculture 



EDWARD P. TERRY 



LIBRARY OF CONGRESS 



DD0ESflbH347 



